formal/hol/Help/ACCEPT_TAC.doc

\DOC ACCEPT_TAC

\TYPE {ACCEPT_TAC : thm_tactic}

\SYNOPSIS
Solves a goal if supplied with the desired theorem (up to alpha-conversion).

\KEYWORDS
tactic.

\DESCRIBE
{ACCEPT_TAC} maps a given theorem {th} to a tactic that solves any goal whose
conclusion is alpha-convertible to the conclusion of {th}.

\FAILURE
{ACCEPT_TAC th (A ?- g)} fails if the term {g} is not alpha-convertible to the
conclusion of the supplied theorem {th}.

\EXAMPLE
The theorem {BOOL_CASES_AX = |- !t. (t <=> T) \/ (t <=> F)} can be used to
solve the goal:
{
  # g `!x. (x <=> T) \/ (x <=> F)`;;
}
\noindent by
{
  # e(ACCEPT_TAC BOOL_CASES_AX);;
  val it : goalstack = No subgoals
}

\USES
Used for completing proofs by supplying an existing theorem, such as an axiom,
or a lemma already proved. Often this can simply be done by rewriting, but
there are times when greater delicacy is wanted.

\SEEALSO
MATCH_ACCEPT_TAC.

\ENDDOC