LIST_INDUCT_TAC : tactic

- STRUCTURE
- SYNOPSIS
- Performs tactical proof by structural induction on lists.
- DESCRIPTION
- LIST_INDUCT_TAC reduces a goal !l.P[l], where l ranges over lists, to two subgoals corresponding to the base and step cases in a proof by structural induction on l. The induction hypothesis appears among the assumptions of the subgoal for the step case. The specification of LIST_INDUCT_TAC is:where l' is a primed variant of l that does not appear free in the assumptions A (usually, l' is just l). When LIST_INDUCT_TAC is applied to a goal of the form !l.P, where l does not appear free in P, the subgoals are just A ?- P and A u {{P}} ?- !h.P.
A ?- !l. P ===================================================== LIST_INDUCT_TAC A |- P[NIL/l] A u {{P[l'/l]}} ?- !h. P[CONS h l'/l]

- FAILURE
- LIST_INDUCT_TAC g fails unless the conclusion of the goal g has the form !l.t, where the variable l has type (ty)list for some type ty.
- SEEALSO

HOL Kananaskis-14