Theorem snocne0 | index | src |

theorem snocne0 (a b: nat): $ a |> b != 0 $;
StepHypRefExpression
1 len0
len 0 = 0
2 leneq
a |> b = 0 -> len (a |> b) = len 0
3 1, 2 syl6eq
a |> b = 0 -> len (a |> b) = 0
4 sucne0
len (a |> b) = suc (len a) -> len (a |> b) != 0
5 4 conv ne
len (a |> b) = suc (len a) -> ~len (a |> b) = 0
6 snoclen
len (a |> b) = suc (len a)
7 5, 6 ax_mp
~len (a |> b) = 0
8 3, 7 mt
~a |> b = 0
9 8 conv ne
a |> b != 0

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)