Theorem dmeq ≪ | index | src | ≫

theorem dmeq (_A1 _A2: set): $ _A1 == _A2 -> Dom _A1 == Dom _A2 $;

Step	Hyp	Ref	Expression
1		id	_A1 == _A2 -> _A1 == _A2
2	1	dmeqd	_A1 == _A2 -> Dom _A1 == Dom _A2

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)