is_imp : term -> bool

SYNOPSIS
Tests a term to see if it is an implication or a negation.

DESCRIBE
If M has the form t1 ==> t2, or the form ~t, then is_imp M returns true. If the term is neither an implication nor a negation the result is false.

FAILURE
Never fails.

COMMENTS
Yields true of negations because dest_imp destructs negations (for backwards compatibility with PPLAMBDA). Use is_imp_only if you don't want this behaviour.

SEEALSO  mk_imp,   dest_imp,   is_imp_only,   dest_imp_only

HOL  Kananaskis 0