Theorem nfor ≪ | index | src | ≫

theorem nfor {x: nat} (a b: wff x): $ F/ x a $ > $ F/ x b $ > $ F/ x a \/ b $;

Step	Hyp	Ref	Expression
1		hyp h1	F/ x a
2	1	nfnot	F/ x ~a
3		hyp h2	F/ x b
4	2, 3	nfim	F/ x ~a -> b
5	4	conv or	F/ x a \/ b

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp), axs_pred_calc (ax_gen, ax_4, ax_5, ax_6, ax_7, ax_10, ax_12)