Theorem lenlt ≪ | index | src | ≫

theorem lenlt (a b: nat): $ a <= b <-> ~b < a $;

Step	Hyp	Ref	Expression
1		con2b	(b < a <-> ~a <= b) -> (a <= b <-> ~b < a)
2		ltnle	b < a <-> ~a <= b
3	1, 2	ax_mp	a <= b <-> ~b < 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_peano (peano1, peano2, peano5, addeq, add0, addS)