Theorem shr12 ≪ | index | src | ≫ 

theorem shr12 (a: nat): $ shr a 1 = a // 2 $;
StepHypRefExpression
1 diveq2 
2 ^ 1 = 2 -> a // 2 ^ 1 = a // 2
2 1 conv shr 
2 ^ 1 = 2 -> shr a 1 = a // 2
3 pow12 
2 ^ 1 = 2
4 2, 3 ax_mp 
shr a 1 = a // 2

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)