Theorem ssri2 ≪ | index | src | ≫

theorem ssri2 (A B: set) {x y: nat}: $ x, y e. A -> x, y e. B $ > $ A C_ B $;

Step	Hyp	Ref	Expression
1		hyp h	x, y e. A -> x, y e. B
2	1	a1i	T. -> x, y e. A -> x, y e. B
3	2	ssrd2	T. -> A C_ B
4	3	trud	A C_ 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)