80 likes | 235 Views
Interval Hybrid Temporal Logic. Altaf Hussain. What is that about …. Definition of Interval hybrid temporal logic minimal interval structures van Benthem minimal interval structures Sound and complete Tableau calculus Technical results. Interval Hybrid temporal logic.
E N D
Interval Hybrid Temporal Logic Altaf Hussain
What is that about … • Definition of Interval hybrid temporal logic • minimal interval structures • van Benthem minimal interval structures • Sound and complete Tableau calculus • Technical results
Interval Hybrid temporal logic Hybrid languages are modal languages which use formulas to refer to specific points in a model. • Basic modal language built over propositional variables = {p, q, r, …}. • Let = {i, j, k, …} be a nonempty set – elements are called nominals and are used to name states • Let ( ) = • ( ) – called the set of atoms and define the interval hybrid logic over ( ) as follows: = i | p | | | | @i where {<D>,<U>,<F>,<P>}, i , p
Interval Hybrid temporal logic Interpretation • Let M = (W, >,<,<|,|>,V), where w W; >,<, … are binary relations on W and V: (W);i , V(i) is a singleton subset of W. • Then M, w |= p iffw V(p) M, w |= iffM, w | M, w |= iffM, w |= and M, w |= M, w |= <D> iff w’(w|>w’ and M, w’ |= ) M, w |= <U> iff w’(w<|w’ and M, w’ |= ) M, w |= <F> iff w’(w<w’ and M, w’ |= ) M, w |= <P> iff w’(w>w’ and M, w’ |= ) M, w |= iiffw V(i) M, w |= @i iffM, w’ |= where w’ is the denotation of i under V.
Interval Hybrid temporal logic Minimal interval structure • F = (W, >,<,<|,|>) is Minimal interval structure if it satisfies: • For >, < Irreflexivity, Transitivity • For |>, <| Reflexivity, Transitivity, Antisymetry and • xy(x < y u(u<|x u<y)) Right monotonicity • xy(x < y u(u<|y x<u)) Left monotonicity • Examples • W = {[n,m] | n m and n,m Z} • <| = {([n,m],[k,l], k n m l} • |> = {([n,m],[k,l], n k l m} • < = {([n,m],[k,l], n m < k l} • > = {([n,m],[k,l], k l < n m} • W = {(n,m) | n < m and n,m Q} • <| = {((n,m),(k,l), k n < m l} • |> = {((n,m),(k,l), n k < l m} • < = {((n,m),(k,l), n < m k < l} • > = {((n,m),(k,l), k < l n < m}
Tableau system • Tableau system is sound and complete • Tree where nodes are labeled by formulas and which is built via certain tableau rules • Some rules (all in the article): , denote formulas and s, t, u and a denote nominals @s |-- @s [] @s |-- @s [] @s () |-- @s , @s [] @s () |-- @s | @s [ ] @s @t |-- @t [@] @s @t |-- @t [@] @s t, @t u |-- @s u [bridge] @s <D>t |-- @t <U>s [C(<|)]
Tableau system • Show that @s (<D>i ) @i (<U> <U>s) is provable. • So we show that there is a closed tableau whose root node is: @k(@s (<D>i ) @i (<U> <U>s)) @k(@s (<D>i ) , @k(@i (<U> <U>s)) [@] @k(@s (<D>i ) , (@i (<U> <U>s)) [] @k@s <D>i, @k@s [ ] @i <U> @i <U>s [@] @s <D>i, @s @s <D>i, @s [C(<|)] @i <U>s [bridge] @i <U>s @i <U>
Technical results • Complexity of the satisfiability problem for minimal interval structures is EXPTIME • The logic minimal interval structures are decidable