unwindLib.EXPAND_ALL_BUT

STRUCTURE

SYNOPSIS

Unfolds, then unwinds all lines (except those specified) as much as possible, then prunes the unwound lines.

LIBRARY

unwind

DESCRIPTION

EXPAND_ALL_BUT_CONV [`li(k+1)`;...;`lim`] thl when applied to the following term:

   "?l1 ... lm. t1 /\ ... /\ ui1 /\ ... /\ uik /\ ... /\ tn"

returns a theorem of the form:

   B |- (?l1 ... lm. t1 /\ ... /\ ui1 /\ ... /\ uik /\ ... /\ tn) =
        (?li(k+1) ... lim. t1' /\ ... /\ tn')

where each ti' is the result of rewriting ti with the theorems in thl. The set of assumptions B is the union of the instantiated assumptions of the theorems used for rewriting. If none of the rewrites are applicable to a conjunct, it is unchanged. Those conjuncts that after rewriting are equations for the lines li1,...,lik (they are denoted by ui1,...,uik) are used to unwind and the lines li1,...,lik are then pruned.

The li’s are related by the equation:

   {{li1,...,lik}} u {{li(k+1),...,lim}} = {{l1,...,lm}}

FAILURE

The function may fail if the argument term is not of the specified form. It will also fail if the unwound lines cannot be pruned. It is possible for the function to attempt unwinding indefinitely (to loop).

EXAMPLE

#EXPAND_ALL_BUT_CONV [`l1`]
# [ASSUME "!in out. INV (in,out) = !(t:num). out t = ~(in t)"]
# "?l1 l2.
#   INV (l1,l2) /\ INV (l2,out) /\ (!(t:num). l1 t = l2 (t-1) \/ out (t-1))";;
. |- (?l1 l2.
       INV(l1,l2) /\ INV(l2,out) /\ (!t. l1 t = l2(t - 1) \/ out(t - 1))) =
     (?l1.
       (!t. out t = ~~l1 t) /\ (!t. l1 t = ~l1(t - 1) \/ ~~l1(t - 1)))

SEEALSO

EXPAND_AUTO_CONV, EXPAND_ALL_BUT_RIGHT_RULE, EXPAND_AUTO_RIGHT_RULE, UNFOLD_CONV, UNWIND_ALL_BUT_CONV, PRUNE_SOME_CONV