Theorem appendeq2d ≪ | index | src | ≫

theorem appendeq2d (_G: wff) (l1 _l21 _l22: nat):
  $ _G -> _l21 = _l22 $ >
  $ _G -> l1 ++ _l21 = l1 ++ _l22 $;

Step	Hyp	Ref	Expression
1		eqidd	_G -> l1 = l1
2		hyp _h	_G -> _l21 = _l22
3	1, 2	appendeqd	_G -> l1 ++ _l21 = l1 ++ _l22

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 (peano2, addeq, muleq)