Theorem nexi ≪ | index | src | ≫

theorem nexi {x: nat} (a: wff x): $ ~a $ > $ ~E. x a $;

Step	Hyp	Ref	Expression
1		alnex	A. x ~a <-> ~E. x a
2		hyp h	~a
3	2	ax_gen	A. x ~a
4	1, 3	mpbi	~E. x a

Axiom use

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