LIST_CONJ : thm list -> thm
STRUCTURE
SYNOPSIS
Conjoins the conclusions of a list of theorems.
DESCRIPTION
         A1 |- t1 ... An |- tn
   ----------------------------------  LIST_CONJ
    A1 u ... u An |- t1 /\ ... /\ tn

FAILURE
LIST_CONJ fails if applied to an empty list of theorems.
SEEALSO
HOL  Kananaskis-14