MK_CONJ : thm -> thm -> thm
A |- p <=> p' B |- q <=> q'
----------------------------------- MK_CONJ
A u B |- p /\ q <=> p' /\ q'
# let th1 = ARITH_RULE `0 < n <=> ~(n = 0)`
and th2 = ARITH_RULE `1 <= n <=> ~(n = 0)`;;
val th1 : thm = |- 0 < n <=> ~(n = 0)
val th2 : thm = |- 1 <= n <=> ~(n = 0)
# MK_CONJ th1 th2;;
val it : thm = |- 0 < n /\ 1 <= n <=> ~(n = 0) /\ ~(n = 0)