Theorem truemul ≪ | index | src | ≫

theorem truemul (a b: nat): $ true (a * b) <-> true a /\ true b $;

Step	Hyp	Ref	Expression
1		mulne0	a * b != 0 <-> a != 0 /\ b != 0
2	1	conv true	true (a * b) <-> true a /\ true b

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp, itru), axs_pred_calc (ax_gen, ax_4, ax_5, ax_6, ax_7, ax_10, ax_11, ax_12), axs_peano (peano1, peano2, peano5, addeq, muleq, add0, addS, mul0, mulS)