theorem shrmodsub (a b c: nat):
$ c <= b -> shr (a % 2 ^ b) c = shr a c % 2 ^ (b - c) $;
| Step | Hyp | Ref | Expression |
|---|
| 1 |
|
shrmodadd2 |
shr (a % 2 ^ (b - c + c)) c = shr a c % 2 ^ (b - c) |
| 2 |
|
npcan |
c <= b -> b - c + c = b |
| 3 |
2 |
eqcomd |
c <= b -> b = b - c + c |
| 4 |
3 |
poweq2d |
c <= b -> 2 ^ b = 2 ^ (b - c + c) |
| 5 |
4 |
modeq2d |
c <= b -> a % 2 ^ b = a % 2 ^ (b - c + c) |
| 6 |
5 |
shreq1d |
c <= b -> shr (a % 2 ^ b) c = shr (a % 2 ^ (b - c + c)) c |
| 7 |
1, 6 |
syl6eq |
c <= b -> shr (a % 2 ^ b) c = shr a c % 2 ^ (b - c) |
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)