Theorem dvdadd2 | index | src |

theorem dvdadd2 (a b n: nat): $ n || a -> (n || b <-> n || b + a) $;
StepHypRefExpression
1 eqidd
a + b = b + a -> n = n
2 id
a + b = b + a -> a + b = b + a
3 1, 2 dvdeqd
a + b = b + a -> (n || a + b <-> n || b + a)
4 addcom
a + b = b + a
5 3, 4 ax_mp
n || a + b <-> n || b + a
6 dvdadd1
n || a -> (n || b <-> n || a + b)
7 5, 6 syl6bb
n || a -> (n || b <-> n || b + a)

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)