Theorem opt0 ≪ | index | src | ≫

theorem opt0 (A: set): $ 0 e. Option A $;

Step	Hyp	Ref	Expression
1		elopt	0 e. Option A <-> 0 = 0 \/ 0 - 1 e. A
2		orl	0 = 0 -> 0 = 0 \/ 0 - 1 e. A
3		eqid	0 = 0
4	2, 3	ax_mp	0 = 0 \/ 0 - 1 e. A
5	1, 4	mpbir	0 e. Option A

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_set (elab, ax_8), axs_the (theid, the0), axs_peano (addeq)