Theorem zltadd2 | index | src |

theorem zltadd2 (a b c: nat): $ b  a +Z b 
    
StepHypRefExpression
1 oddeq
b -Z c = a +Z b -Z (a +Z c) -> (odd (b -Z c) <-> odd (a +Z b -Z (a +Z c)))
2 1 conv zlt
b -Z c = a +Z b -Z (a +Z c) -> (b <Z c <-> a +Z b <Z a +Z c)
3 eqcom
a +Z b -Z (a +Z c) = b -Z c -> b -Z c = a +Z b -Z (a +Z c)
4 zpnpcan2
a +Z b -Z (a +Z c) = b -Z c
5 3, 4 ax_mp
b -Z c = a +Z b -Z (a +Z c)
6 2, 5 ax_mp
b <Z c <-> a +Z b <Z a +Z c

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), axs_the (theid, the0), axs_peano (peano1, peano2, peano5, addeq, muleq, add0, addS, mul0, mulS)