IPC - International Patent Classification Basics

1. IPC - International Patent Classification Basics

2. Basics of IPC The following presentation addresses: ? Elements of IPC scheme: - symbols, hierarchy, titles - other elements of IPC scheme ? Scope, filescope, effective scope of IPC places This presentation introduces basic features of the IPC, in particular all the elements that build up the IPC scheme, i.e. symbols and their format, titles of IPC places, the hierarchy of these places, references in titles, notes following titles, guidance headings, subclass and class indices. In addition, important terminology is introduced: the "scope" of IPC entries, i.e. the technical subject matter that is covered by an IPC place, the "filescope", and the "effective scope". It also addresses the problem of overlap of scope of different places.This presentation introduces basic features of the IPC, in particular all the elements that build up the IPC scheme, i.e. symbols and their format, titles of IPC places, the hierarchy of these places, references in titles, notes following titles, guidance headings, subclass and class indices. In addition, important terminology is introduced: the "scope" of IPC entries, i.e. the technical subject matter that is covered by an IPC place, the "filescope", and the "effective scope". It also addresses the problem of overlap of scope of different places.

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4. Format of IPC Symbols A23G 9/02 is a symbol representing an IPC group. Any group symbol consists of different components: The first letter indicates the section of the IPC to which it belongs; there are 8 sections represented by the letters A, B,..H. The section letter and the following two digits represent a class symbol. Adding another letter to the class symbol generates the symbol of a subclass being part of the class. After this subclass part of the symbol follows the group part which consist of two different elements separated by a stroke: the main group part and the subgroup part. The formatting shown above with a space between the subclass part and the group parts and a slash between the two group parts is the offical format of IPC symbols that should be used for presenting IPC symbols. However, sometimes different presentations can be found or used for searching databases, e.g. no space after the subclass part, or a dash instead of a stroke. A23G 9/02 is a symbol representing an IPC group. Any group symbol consists of different components: The first letter indicates the section of the IPC to which it belongs; there are 8 sections represented by the letters A, B,..H. The section letter and the following two digits represent a class symbol. Adding another letter to the class symbol generates the symbol of a subclass being part of the class. After this subclass part of the symbol follows the group part which consist of two different elements separated by a stroke: the main group part and the subgroup part. The formatting shown above with a space between the subclass part and the group parts and a slash between the two group parts is the offical format of IPC symbols that should be used for presenting IPC symbols. However, sometimes different presentations can be found or used for searching databases, e.g. no space after the subclass part, or a dash instead of a stroke.

5. IPC group symbols Accordingly, there are two different types of groups: main groups and subgroups. If only "groups" are mentioned in the following, both types of groups are addressed. Main groups always have "00" after the slash; subgroups have any other combination of digits. Currently, main group symbols have between 1 and 3 digits on the left hand side although WIPO Standard ST.8 allows up to 4 digits. For the subgroup part, up to six digits can be used. At least two digits have to be used. It should be noted that patent documents are usually classified either by using main group or subgroup symbols. Very few countries make use of the option to use only subclass symbols - an option that is possible according to the Strasbourg Agreement. The symbols of sections, classes or subclasses are usually only used in the scheme for describing its hierarchical structure.Accordingly, there are two different types of groups: main groups and subgroups. If only "groups" are mentioned in the following, both types of groups are addressed. Main groups always have "00" after the slash; subgroups have any other combination of digits. Currently, main group symbols have between 1 and 3 digits on the left hand side although WIPO Standard ST.8 allows up to 4 digits. For the subgroup part, up to six digits can be used. At least two digits have to be used. It should be noted that patent documents are usually classified either by using main group or subgroup symbols. Very few countries make use of the option to use only subclass symbols - an option that is possible according to the Strasbourg Agreement. The symbols of sections, classes or subclasses are usually only used in the scheme for describing its hierarchical structure.

6. IPC logical/hierarchical structure The IPC is a hierarchical system. At the top level, there are 8 different sections covering very broadly different areas of technology.The IPC is a hierarchical system. At the top level, there are 8 different sections covering very broadly different areas of technology.

7. IPC hierarchical structure Each section is subdivided in classes, each class in subclasses, each subclass in main groups, and many but not all main groups in subgroups. Subgroups can again be subdivided in further subgroups. Thus, below main groups there can be many further hierarchical levels. However, they all are called subgroups. These subgroups are distinguished by so-called "dots" indicating their hierarchical position (please see the 2nd next slide). It is important to note that only group symbols are used for classifying patents (very few countries use only subclass symbols).Each section is subdivided in classes, each class in subclasses, each subclass in main groups, and many but not all main groups in subgroups. Subgroups can again be subdivided in further subgroups. Thus, below main groups there can be many further hierarchical levels. However, they all are called subgroups. These subgroups are distinguished by so-called "dots" indicating their hierarchical position (please see the 2nd next slide). It is important to note that only group symbols are used for classifying patents (very few countries use only subclass symbols).

8. IPC hierarchical structure The following slide shows in more detail a subdivision of the hierarchical path which is indicated in the above slide in blue.The following slide shows in more detail a subdivision of the hierarchical path which is indicated in the above slide in blue.

9. This slide illustrates the deep subdivision into many hierarchical subgroup levels below the main group level, and explains the need for it. Below main groups, the hierarchical levels of subgroups are indicated by dots. Each additional dot indicates an additional lower level, i.e. a further subdivison of a subgroup. For example, the 7-dot subgroup H01F 1/055 is subdivided in 3 different 8-dot subgroups. Why do we need such a fine subdivision? In the main group H01F 1/00 there are so many documents classified that an effective inspection of each single document at search is not efficient. Only the more specific and hierarchically lower subgroups, e.g. H01F 1/057, contain fewer documents, the number being low enough for allowing an efficient inspection of each single document. The bottom line is, that the hierarchically lowest groups should be populated only by a reasonable number of documents that allow an efficient intellectual inspection of all documents. If the number of documents grows too large, revision of such groups may be needed in order to create finer subdivisions. The numbers of documents given as examples were established in 2005 and have changed since.This slide illustrates the deep subdivision into many hierarchical subgroup levels below the main group level, and explains the need for it. Below main groups, the hierarchical levels of subgroups are indicated by dots. Each additional dot indicates an additional lower level, i.e. a further subdivison of a subgroup. For example, the 7-dot subgroup H01F 1/055 is subdivided in 3 different 8-dot subgroups. Why do we need such a fine subdivision? In the main group H01F 1/00 there are so many documents classified that an effective inspection of each single document at search is not efficient. Only the more specific and hierarchically lower subgroups, e.g. H01F 1/057, contain fewer documents, the number being low enough for allowing an efficient inspection of each single document. The bottom line is, that the hierarchically lowest groups should be populated only by a reasonable number of documents that allow an efficient intellectual inspection of all documents. If the number of documents grows too large, revision of such groups may be needed in order to create finer subdivisions. The numbers of documents given as examples were established in 2005 and have changed since.

10. Hierarchy of Subgroups The hierarchical level of a subgroup is only indicated by the number of its dots! The numbering of the subgroups does not give any information on the hierarchical level. For example the subgroup G01N 33/483 is two levels higher than then the group 33/49 which has only 2 digits after the slash.The hierarchical level of a subgroup is only indicated by the number of its dots! The numbering of the subgroups does not give any information on the hierarchical level. For example the subgroup G01N 33/483 is two levels higher than then the group 33/49 which has only 2 digits after the slash.

11. Numbering does not determine hierarchical level Numbering determines sequential order of subgroups Numbering of subgroups However, the numbering does provide some information, namely, the sequential order of the groups. If a main group comprises several one-dot subgroups these subgroups have to be brought in specific sequential order which can be prescribed by the numbers given. The slash can be interpreted as a decimal point and the sequence of groups is determined by the numerical value of the resulting number.However, the numbering does provide some information, namely, the sequential order of the groups. If a main group comprises several one-dot subgroups these subgroups have to be brought in specific sequential order which can be prescribed by the numbers given. The slash can be interpreted as a decimal point and the sequence of groups is determined by the numerical value of the resulting number.

12. IPC hierarchical structure This slide illustrates the number of the different hierarchical entities in IPC 2009. More specific numbers for different versions are available on the website http://www.wipo.int/classifications/ipc/en/ITsupport/, e.g. for IPC 2009 at http://www.wipo.int/classifications/ipc/en/ITsupport/Version20090101/transformations/stats.html.This slide illustrates the number of the different hierarchical entities in IPC 2009. More specific numbers for different versions are available on the website http://www.wipo.int/classifications/ipc/en/ITsupport/, e.g. for IPC 2009 at http://www.wipo.int/classifications/ipc/en/ITsupport/Version20090101/transformations/stats.html.

13. Titles and scope IPC symbols are always combined with titles. Such a combination is also called an �IPC place�, �IPC entry� or a �classification place�. Because of the terminology used in other contexts (e.g. USPTO patent classification), some people sometimes call such an entry in the IPC an �IPC class� or simply �class�. However, this is incorrect because, in the IPC, a class is an entry at quite a high hierarchical level, which is not used for classifying documents (remember, only group symbols are used for classifying documents). The scope of a place is all the technical subject matter that could be classified in this place. Titles are the most important elements of the IPC scheme that describe the scope. As we shall see below, other elements of the IPC scheme also have an effect of the scope of place. IPC symbols are always combined with titles. Such a combination is also called an �IPC place�, �IPC entry� or a �classification place�. Because of the terminology used in other contexts (e.g. USPTO patent classification), some people sometimes call such an entry in the IPC an �IPC class� or simply �class�. However, this is incorrect because, in the IPC, a class is an entry at quite a high hierarchical level, which is not used for classifying documents (remember, only group symbols are used for classifying documents). The scope of a place is all the technical subject matter that could be classified in this place. Titles are the most important elements of the IPC scheme that describe the scope. As we shall see below, other elements of the IPC scheme also have an effect of the scope of place.

14. Examples of titles In the above example, class A47 has a so-called multi-part title, i.e. the title consists of several parts separated by a semicolon. Other places in the IPC have a single part title, e.g. subclass A01J. Multi-part titles are used in cases where one wishes to group together similar items and where it is difficult to find a generic common description. Each title part should be interpreted as separate title.In the above example, class A47 has a so-called multi-part title, i.e. the title consists of several parts separated by a semicolon. Other places in the IPC have a single part title, e.g. subclass A01J. Multi-part titles are used in cases where one wishes to group together similar items and where it is difficult to find a generic common description. Each title part should be interpreted as separate title.

15. Subgroup titles The titles of subgroups sometimes start with an upper case letter, sometimes with a lower case letter. Titles starting with an upper case letter are self consistent, complete titles, while titles with lower case letters are incomplete and need to be complemented by the hierarchically preceding title. There is no specific reason why titles are sometimes presented the one or the other way. The lower case option simply allows to have shorter titles.The titles of subgroups sometimes start with an upper case letter, sometimes with a lower case letter. Titles starting with an upper case letter are self consistent, complete titles, while titles with lower case letters are incomplete and need to be complemented by the hierarchically preceding title. There is no specific reason why titles are sometimes presented the one or the other way. The lower case option simply allows to have shorter titles.

16. Attention ! This slide draws attention to an aspect which important when combining titles: When completing a lower case title one has to pay attention to hierarchy: one must not use the preceding title but the hierarchically preceding title. As such, 5/08 has to be combined with 5/00 and not with 5/06 which is the immediatley preceding one but on the same hierachical level.This slide draws attention to an aspect which important when combining titles: When completing a lower case title one has to pay attention to hierarchy: one must not use the preceding title but the hierarchically preceding title. As such, 5/08 has to be combined with 5/00 and not with 5/06 which is the immediatley preceding one but on the same hierachical level.

17. Scope of IPC entries The scope of places in the IPC is primarily defined by the titles of these places; the titles serve as description of the technical subject matter. Titles of sections and classes that comprise many different subject matters are necessarily very broad. They may be so broad that it is not straightforward whether some very specific subject matter is covered by a section or class. For example, the title "Transporting" of section B does not immediately indicate that section B covers "vehicle suspensions" in subclass B60G. On the other hand, the titles of subclasses and groups are worded such that they describe as precisely as possible the subject matter that they are intended to cover. The scope of places in the IPC is primarily defined by the titles of these places; the titles serve as description of the technical subject matter. Titles of sections and classes that comprise many different subject matters are necessarily very broad. They may be so broad that it is not straightforward whether some very specific subject matter is covered by a section or class. For example, the title "Transporting" of section B does not immediately indicate that section B covers "vehicle suspensions" in subclass B60G. On the other hand, the titles of subclasses and groups are worded such that they describe as precisely as possible the subject matter that they are intended to cover.

18. Complex example This slide returns to the previous example of a very deep subdevision in order to illustrate the combining of titles at different hierarchical levels to one single title. Redundant wording was removed. This example also illustrates another reason for having a hierarchical structure: Very long titles can be split up in different details and be shared with other groups that also have these details. This also facilitates the browsing of the IPC from less complex to more complex subject matter.This slide returns to the previous example of a very deep subdevision in order to illustrate the combining of titles at different hierarchical levels to one single title. Redundant wording was removed. This example also illustrates another reason for having a hierarchical structure: Very long titles can be split up in different details and be shared with other groups that also have these details. This also facilitates the browsing of the IPC from less complex to more complex subject matter.

19. IPC without hierarchy ? This is the time to answer a questions that is sometimes asked to the International Bureau: Are there also tables available (e.g. Excel sheets) that simply list all IPC symbols and their associated titles ? Answer: No. That would make little sense because some titles are incomplete, and, above all, because a title has to be read in combination with ist hierarchically preceding titles; otherwise its scope may be misinterpreted.This is the time to answer a questions that is sometimes asked to the International Bureau: Are there also tables available (e.g. Excel sheets) that simply list all IPC symbols and their associated titles ? Answer: No. That would make little sense because some titles are incomplete, and, above all, because a title has to be read in combination with ist hierarchically preceding titles; otherwise its scope may be misinterpreted.

20. Overlap, similarity of scopes A61B 5/00 Measuring for diagnostic purposes ? G01 Measuring F16F Springs; Shock absorbers ? B60G Vehicle suspensions This slide introduces the similarity or overlap of scopes of different places in the IPC, which sometimes complicates the use of the IPC for less experienced users who are not aware of the existence of places covering similar subject matter. There is already some similarity of scope between different sections. For example, class G01 in section G for "Physics" covers all different types of measuring or analysis of samples. On the other hand, measuring or analysis for medical purposes is found in section A for "Human Necessities", in particular in main group A61B 5/00. Similarly, subclass F16D in section F for "Mechanical Engineering" covers shock absorbers as such, while subclass B60G in section B for "Transporting" covers vehicle suspensions.This slide introduces the similarity or overlap of scopes of different places in the IPC, which sometimes complicates the use of the IPC for less experienced users who are not aware of the existence of places covering similar subject matter. There is already some similarity of scope between different sections. For example, class G01 in section G for "Physics" covers all different types of measuring or analysis of samples. On the other hand, measuring or analysis for medical purposes is found in section A for "Human Necessities", in particular in main group A61B 5/00. Similarly, subclass F16D in section F for "Mechanical Engineering" covers shock absorbers as such, while subclass B60G in section B for "Transporting" covers vehicle suspensions.

21. Scope of IPC Groups This slide illustrates overlap between subgroups of the same main group. If different subgroups specify different characteristics that may both be present in a particular object, this creates automatically some overlap. In the above example, organic materials may also have polarizing effects. The circles symbolically encompass/delineate (as in mathematical set theory) the subject matter covered by a group.This slide illustrates overlap between subgroups of the same main group. If different subgroups specify different characteristics that may both be present in a particular object, this creates automatically some overlap. In the above example, organic materials may also have polarizing effects. The circles symbolically encompass/delineate (as in mathematical set theory) the subject matter covered by a group.

22. Scope of IPC Groups This slide illustrates the rather ideal case that all subgroups of main group 1/00 do not overlap, i.e. are mutually exclusive ( the circles do not overlap).This slide illustrates the rather ideal case that all subgroups of main group 1/00 do not overlap, i.e. are mutually exclusive ( the circles do not overlap).

23. Filescope ? Some more terminology: Filescope of an IPC entry: Scope of an entry minus the scope of all its hierchically lower places i.e. all documents that are actually classified in a particular IPC place Remember: Scope of an IPC entry: Subject matter that could be classified there based on its title, references, notes This slide introduces some additional important terminology: the "file scope" in comparison to the "scope". The next following slide provides a graphical illustration.This slide introduces some additional important terminology: the "file scope" in comparison to the "scope". The next following slide provides a graphical illustration.

24. File scope of IPC Groups This slide illustrates another important concept, the �file scope� of IPC places. The filescope is either equal to the scope of a group or smaller. The left hand circle illustrates the scope of a main group 1/00. If this main group has no subgroups, the scope and the file scope are equal. In the right hand example, the main group 1/00 has subgroups. These subgroups take some of the documents that could also be classified by using the main group symbol but which better fit in the more specific subgroups. Therefore, fewer documents remain in the main group. The file scope is this remainder, i.e. the scope of a group minus the scope of all its subgroups. This slide illustrates another important concept, the �file scope� of IPC places. The filescope is either equal to the scope of a group or smaller. The left hand circle illustrates the scope of a main group 1/00. If this main group has no subgroups, the scope and the file scope are equal. In the right hand example, the main group 1/00 has subgroups. These subgroups take some of the documents that could also be classified by using the main group symbol but which better fit in the more specific subgroups. Therefore, fewer documents remain in the main group. The file scope is this remainder, i.e. the scope of a group minus the scope of all its subgroups.

25. Elements of IPC scheme Classification places: Symbol + Title + Hierarchy References in titles: > Statements in brackets in titles pointing to other places > they apply to the place where they appear and to all hierarchically lower places, unless stated differently Until now we have learned about two fundamental elements of the IPC scheme: symbols and their associated titles, plus the hierarchical order. However, the IPC scheme has additional elements that are relevant for defining the scope of places, and elements that simply facilitate the use of the scheme. The next such elements are references. They appear in titles of subclasses and groups and are statements in brackets that point to one or more other places in the IPC which cover similar or related subject matter. For IPC versions which are older than the future version IPC 2011, references also occur in some class titles or guidance headings. However, with IPC 2011 all such references will have been removed.Until now we have learned about two fundamental elements of the IPC scheme: symbols and their associated titles, plus the hierarchical order. However, the IPC scheme has additional elements that are relevant for defining the scope of places, and elements that simply facilitate the use of the scheme. The next such elements are references. They appear in titles of subclasses and groups and are statements in brackets that point to one or more other places in the IPC which cover similar or related subject matter. For IPC versions which are older than the future version IPC 2011, references also occur in some class titles or guidance headings. However, with IPC 2011 all such references will have been removed.

26. Examples of references This slides illustrates different examples of references.This slides illustrates different examples of references.

27. References In principle there are two different types of references which are traditionally called limiting or informative references. Limiting references help defining the scope of a place. They are used in case of overlap between two different places in the IPC, and solve this overlap problem by giving priority to one of the places. They are thus found in the place which must not be used and point to the other place which must be used. Some of these limiting references are specifically worded "... takes precendence". For the purpose of reciprocity, one might also expect another reference in the other place that is given priority. However, this is not the case. In the past, i.e. in older versions of the IPC such references indicating the other place have sometimes been included; because they were not limiting, they were called "informative" as they point to place that should not be used for classifying but that could be interesting for search purposes because it covers related subject matter. However, in the future all of those references will be removed from the scheme and be available only in the electronic layer. That will allow to more easily distinguish between these different types of references.In principle there are two different types of references which are traditionally called limiting or informative references. Limiting references help defining the scope of a place. They are used in case of overlap between two different places in the IPC, and solve this overlap problem by giving priority to one of the places. They are thus found in the place which must not be used and point to the other place which must be used. Some of these limiting references are specifically worded "... takes precendence". For the purpose of reciprocity, one might also expect another reference in the other place that is given priority. However, this is not the case. In the past, i.e. in older versions of the IPC such references indicating the other place have sometimes been included; because they were not limiting, they were called "informative" as they point to place that should not be used for classifying but that could be interesting for search purposes because it covers related subject matter. However, in the future all of those references will be removed from the scheme and be available only in the electronic layer. That will allow to more easily distinguish between these different types of references.

28. Precedence references Precedence references are a special example of limiting references, they always have the specific wording �... takes precedence�. The example is the one from slide 21. The reference in the title of 1/04 removes the overlap with 1/08. Any optical elements using polarizing organic material must be classified in 1/08.Precedence references are a special example of limiting references, they always have the specific wording �... takes precedence�. The example is the one from slide 21. The reference in the title of 1/04 removes the overlap with 1/08. Any optical elements using polarizing organic material must be classified in 1/08.

29. This slide summarizes the differences between limiting and informative references. It underlines that limiting references are relevant to classification of documents, pointing to places were some subject matter has to be classified, while informative references are primarily important for search purposes, pointing to related areas.This slide summarizes the differences between limiting and informative references. It underlines that limiting references are relevant to classification of documents, pointing to places were some subject matter has to be classified, while informative references are primarily important for search purposes, pointing to related areas.

30. This slide explains that the strong distinction of the previous slide has limitations. Informative references can also be interesting for classification purposes. If one has incidentally found a place in the IPC that appears to be somehow related to the subject matter that one wishes to classify, an informative reference there may point to another place covering related subject matter. Closer analysis of the subject matter to classified may reveal then that the other place even better fits the subject matter. Similarly, limiting references may also direct a searcher to other places which cover similar subject matter that is also of interest for search purposes.This slide explains that the strong distinction of the previous slide has limitations. Informative references can also be interesting for classification purposes. If one has incidentally found a place in the IPC that appears to be somehow related to the subject matter that one wishes to classify, an informative reference there may point to another place covering related subject matter. Closer analysis of the subject matter to classified may reveal then that the other place even better fits the subject matter. Similarly, limiting references may also direct a searcher to other places which cover similar subject matter that is also of interest for search purposes.

31. Removal of informative references Limiting or informative references are not identified as such in scheme > Ambiguity Informative references will in future be removed from the IPC scheme and be available in Definitions of the e-layer only This will abolish ambiguity; any reference in the scheme can in future be regarded as limiting In some cases it is not very clear whether a reference is strictly limiting or informative and therefore could create ambiguity in classification practice. When the IPC was reformed, the CE has therefore decided to remove all informative references from the scheme and move them to the electronic layer, i.e. the definitions of subclasses or groups. However, this is an still ongoing task; all subclasses have to be reviewed systematically. The status of this removal task is summarized in a regularly updated table to be found on the IPC e-forum in project WG/191. In some cases it is not very clear whether a reference is strictly limiting or informative and therefore could create ambiguity in classification practice. When the IPC was reformed, the CE has therefore decided to remove all informative references from the scheme and move them to the electronic layer, i.e. the definitions of subclasses or groups. However, this is an still ongoing task; all subclasses have to be reviewed systematically. The status of this removal task is summarized in a regularly updated table to be found on the IPC e-forum in project WG/191.

32. Elements of IPC scheme Classification places: Symbol + Title + Hierarchy References Notes: > Separate statements after entries > Apply only to the place where they are, including all hierarchically lower places > Explain scope (G01N 21/00) > Define terminology (B22F, G02) > Indicate classification rules (note 5 after G01R) Notes are a third type of elements of the IPC scheme. They are supplementary statements that follow an IPC entry, e.g. a subclass title. Notes only apply in the area of the IPC where they appear, i.e a note after a subclass title only applies to this subclass; a note after a main group applies only in this main group;... They have different functions: They explain the scope (�this subclass covers ...�; �this subclass does not cover ...�) They define terminology if some terms should be interpreted with a special meaning in the context of the IPC area to which this notes applies. They indicate classification rules that apply in the area.Notes are a third type of elements of the IPC scheme. They are supplementary statements that follow an IPC entry, e.g. a subclass title. Notes only apply in the area of the IPC where they appear, i.e a note after a subclass title only applies to this subclass; a note after a main group applies only in this main group;... They have different functions: They explain the scope (�this subclass covers ...�; �this subclass does not cover ...�) They define terminology if some terms should be interpreted with a special meaning in the context of the IPC area to which this notes applies. They indicate classification rules that apply in the area.

33. Classification places: Symbol + Title + Hierarchy References Notes Guidance headings: > titles without symbols, preceding several main groups > describe common subject matter of several main groups Example: A01B 3/00 - 17/00 Elements of IPC scheme Guidance headings are simply headings for several main groups that cover similar subject matter. They may for example appear in subclasses with multipart titles or very broad titles. They only serve for giving some guidance when browsing the IPC. i.e. they faciliate ist use. With the reformed IPC they have no relevance for definimng the scope of places under them. That was different with the pre-reform IPC where some guidance headings also were relevant for defining the scope; e.g. they could contain limiting references. However, with the reformed IPC all references have been removed from guidance headings.Guidance headings are simply headings for several main groups that cover similar subject matter. They may for example appear in subclasses with multipart titles or very broad titles. They only serve for giving some guidance when browsing the IPC. i.e. they faciliate ist use. With the reformed IPC they have no relevance for definimng the scope of places under them. That was different with the pre-reform IPC where some guidance headings also were relevant for defining the scope; e.g. they could contain limiting references. However, with the reformed IPC all references have been removed from guidance headings.

34. Elements of IPC scheme Classification places: Symbol + Title + Hierarchy References Notes Guidance headings Subclass indices: > list of main groups after some subclass titles > i.e. informative summary In some subclasses, in particular such with many main groups and subgroups, subclass indices are provided after the subclass title which give a broad overview over the main groups of a subclass. They allow to find a suitable main group more easily by avoiding any scrolling.In some subclasses, in particular such with many main groups and subgroups, subclass indices are provided after the subclass title which give a broad overview over the main groups of a subclass. They allow to find a suitable main group more easily by avoiding any scrolling.

35. Elements of IPC scheme Classification places: Symbol + Title + Hierarchy References Notes Guidance headings Subclass indices Class index: > list of subclasses & main groups; > i.e. informative summary Class indices are similar to subclass indices. There is only one, which can be found in G10.Class indices are similar to subclass indices. There is only one, which can be found in G10.

36. Classification places: Symbol + Title + Hierarchy References Notes Guidance headings Subclass indices Class indices Subsections: > informative headings, grouping of classes; > in some sections Elements of IPC scheme

37. Classification places: Symbol + Title + Hierarchy References Notes Guidance headings Subclass indices Class indices Subsections Elements of IPC scheme This slide summarizes the different elements of the IPC scheme and emphasizes that titles, hierarchically higher titles, notes and references have an impact on the scope of a plase.This slide summarizes the different elements of the IPC scheme and emphasizes that titles, hierarchically higher titles, notes and references have an impact on the scope of a plase.

38. Classification places: symbol + title + hierarchy References Notes Guidance headings Subclass indices Class indices Subsections Elements of IPC scheme Guidance headings and any indices have no impact on the scope of places. They only facilitate the use of the IPC, e.g. the browsing of the IPC.Guidance headings and any indices have no impact on the scope of places. They only facilitate the use of the IPC, e.g. the browsing of the IPC.

39. Effective Scope The Guide does not explicitly distinguish between the scope of a place and the effective scope. However, this destinction may be useful in order to emphasize that the wording of a title and the titles of the hierarchically preceding places alone do often not properly define the scope of a place and that other elements also have an important effect on the scope, such as notes which may specifically exclude certain matter, or limitimg references (even such references in hierarchically higher places!) It may also happen that the title is not generic enough to cover explicitly all subject matter of the main groups of a subclass. In such a case, the scope of the main group is implicitly included.The Guide does not explicitly distinguish between the scope of a place and the effective scope. However, this destinction may be useful in order to emphasize that the wording of a title and the titles of the hierarchically preceding places alone do often not properly define the scope of a place and that other elements also have an important effect on the scope, such as notes which may specifically exclude certain matter, or limitimg references (even such references in hierarchically higher places!) It may also happen that the title is not generic enough to cover explicitly all subject matter of the main groups of a subclass. In such a case, the scope of the main group is implicitly included.

40. Effective Scope In comparison to subclasses, the effective scope of groups is also affected by their subclass and the hierarchically higher groups.In comparison to subclasses, the effective scope of groups is also affected by their subclass and the hierarchically higher groups.