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THE GAINS AND THE PITFALLS OF REIFICATION - THE CASE OF ALGEBRA. ANNA SFARD AND LIORA LINCHEVSKI. Definition. Development of Algebra. Problem 3 (Dina’s case).
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THE GAINS AND THE PITFALLS OF REIFICATION -THE CASE OF ALGEBRA ANNA SFARD AND LIORA LINCHEVSKI
Definition Development of Algebra Problem 3 (Dina’s case)
What one actually sees in algebraic symbols depends on the requirements of the problem to which they are applied. Not less important, it depends on what one is able to perceive and prepared to notice. String of symbols Description of a computational process. Function as an object Result of the process- product of a computation A function - a mapping which translates every number into another
Problem 3 • יש פתרון לכל ערך של k? • האם זה נכון שלמערכת הבאה של משוואות לינאריות:
התשובה הצפויה: • כן, כי לכל ערך של K הישר y=k-2 הוא מקביל לציר ה-X, הישר y=k-x הוא משופע ולכן הם נחתכים.
פתרון של דינה אז מה הבעיה? פתרון של יאנה
Reification • The theory of reification is introduced, according to which there is an inherent process-object duality in the majority of mathematical concepts. • It is the basic tenet of our theory that the operational (process-oriented) conception emerges first and that the mathematical objects (structural conceptions) develop afterward through reification of the processes.
The case of algebra-Reification • Abstract objects, such as functions or sets, play the role of links between the old and the new knowledge. In algebra, function is what ties together the arithmetical processes (primary processes) and the formal algebraic manipulations (secondary processes). Thus, reification of the primary processes, or, in the case of algebra, the acquisition of the structural functional outlook, is a warranty of relational understanding. Illustration
האם לערכים בטבלה יש תכונה או תבנית מסוימת? טל: אם נחסיר מספרים באלכסון ונחבר אותם באלכסון נקבל אותו המספר. ... טל: בדקתי עוד דוגמאות, נראה לי שזה עובד. ... .שירלי: אם הייתה לנו נוסחה, משהו כללי...
Historical/ Didactical Parallel • The nature and the growth of algebraic thinking is presented as a sequence of ever more advanced transitions from operational to structural outlook.