IMP_TRANS : (thm -> thm -> thm)
STRUCTURE
SYNOPSIS
Implements the transitivity of implication.
DESCRIPTION
When applied to theorems A1 |- t1 ==> t2 and A2 |- t2 ==> t3, the inference rule IMP_TRANS returns the theorem A1 u A2 |- t1 ==> t3.
    A1 |- t1 ==> t2   A2 |- t2 ==> t3
   -----------------------------------  IMP_TRANS
         A1 u A2 |- t1 ==> t3

FAILURE
Fails unless the theorems are both implicative, with the consequent of the first being the same as the antecedent of the second (up to alpha-conversion).
SEEALSO
HOL  Kananaskis-14