File: FORALL_EQ.doc

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\DOC FORALL_EQ

\TYPE {FORALL_EQ : (term -> thm -> thm)}

\SYNOPSIS
Universally quantifies both sides of an equational theorem.

\KEYWORDS
rule, quantifier, universal, equality.

\DESCRIBE
When applied to a variable {x} and a theorem {A |- t1 = t2}, whose conclusion
is an equation between boolean terms, {FORALL_EQ} returns the
theorem {A |- (!x. t1) = (!x. t2)}, unless the variable {x} is free in any
of the assumptions.
{
         A |- t1 = t2
   ------------------------  FORALL_EQ "x"      [where x is not free in A]
    A |- (!x.t1) = (!x.t2)
}
\FAILURE
Fails if the theorem is not an equation between boolean terms, or if the
supplied term is not simply a variable, or if the variable is free in any of
the assumptions.

\SEEALSO
AP_TERM, EXISTS_EQ, SELECT_EQ.

\ENDDOC