Theorem ltnlt | index | src |

theorem ltnlt (a b: nat): $ a < b -> ~b < a $;
StepHypRefExpression
1 ltnle
a < b <-> ~b <= a
2 con3
(b < a -> b <= a) -> ~b <= a -> ~b < a
3 ltle
b < a -> b <= a
4 2, 3 ax_mp
~b <= a -> ~b < a
5 1, 4 sylbi
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)