Theorem alanex | index | src |

theorem alanex {x: nat} (a b: wff x): $ A. x a /\ E. x b -> E. x (a /\ b) $;
StepHypRefExpression
1 exim
A. x (b -> a /\ b) -> E. x b -> E. x (a /\ b)
2 ian
a -> b -> a /\ b
3 2 alimi
A. x a -> A. x (b -> a /\ b)
4 1, 3 syl
A. x a -> E. x b -> E. x (a /\ b)
5 4 imp
A. x a /\ E. x b -> E. x (a /\ b)

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp), axs_pred_calc (ax_gen, ax_4)