Theorem appslams | index | src |

theorem appslams (a b: nat) {x: nat} (A: set x):
  $ (\\ x, A) @ (a, b) = (S[a / x] A) @ b $;
StepHypRefExpression
1 theeq
{a1 | (a, b), a1 e. (\\ x, A)} == {a1 | b, a1 e. S[a / x] A} -> the {a1 | (a, b), a1 e. (\\ x, A)} = the {a1 | b, a1 e. S[a / x] A}
2 1 conv app
{a1 | (a, b), a1 e. (\\ x, A)} == {a1 | b, a1 e. S[a / x] A} -> (\\ x, A) @ (a, b) = (S[a / x] A) @ b
3 prelslams
(a, b), a1 e. (\\ x, A) <-> b, a1 e. S[a / x] A
4 3 abeqi
{a1 | (a, b), a1 e. (\\ x, A)} == {a1 | b, a1 e. S[a / x] A}
5 2, 4 ax_mp
(\\ x, A) @ (a, b) = (S[a / x] A) @ b

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)