REWR_CONV_A

`REWR_CONV_A`

Conv.REWR_CONV_A : (thm -> conv)

Uses an instance of a given equation to rewrite a term.

REWR_CONV_A th behaves as REWR_CONV th except that it allows substitution of variables or type variables which appear in the hypotheses of th.

Consider the theorem th

   [0 < n] |- (a * n = b * (n : int)) <=> (a = b)

and the term tm

   f (a * m = b * (m : int)) x

Then DEPTH_CONV (REWR_CONV_A th) tm returns

   [0 < m] |- f (a * m = b * m) x <=> f (a = b) x

Likewise, when the goal is tm above, e (VALIDATE (CONV_TAC (DEPTH_CONV (REWR_CONV_A th)))) gives the two subgoals:

      f (a = b) x

      0 < m