Theorem Sumld ≪ | index | src | ≫ 

theorem Sumld (A B: set) (G: wff) (a: nat):
  $ G -> a e. A $ >
  $ G -> b0 a e. Sum A B $;
StepHypRefExpression
1 Suml 
b0 a e. Sum A B <-> a e. A
2 hyp h 
G -> a e. A
3 1, 2 sylibr 
G -> b0 a e. Sum 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)