Drule.IRULE

STRUCTURE

SYNOPSIS

Canonicalises a theorem for use as an introduction rule.

DESCRIPTION

A call to IRULE_CANON th returns a theorem th' that is equivalent to th, but syntactically rearranged to be in the form

   !v1 .. vn. c1 /\ c2 ... /\ cm ==> c

(also allowing for no conjuncts at all). The variables v1 to vn all occur in the conclusion c, which is not universally quantified, nor an implication.

Each of the conjuncts is of the form

   ?ev1 .. evi. ec1 /\ .. ecj

where it is possible that there are not existentially quantified variables. The existential quantification ensures that there are no free variables in the output theorem th'.

FAILURE

Never fails.

COMMENTS

This function is used within the implementation of irule. The output theorem th' is appropriate for use as an argument to MATCH_MP_TAC (if the output is a quantified implication), or MATCH_ACCEPT_TAC if the output is not an implication.

SEEALSO

irule, MATCH_MP_TAC, RES_CANON