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Metamath Proof Explorer
Description: A monoid homomorphism preserves zero. (Contributed by Mario Carneiro, 7-Mar-2015)
|
|
Ref |
Expression |
|
Hypotheses |
mhm0.z |
|
|
|
mhm0.y |
|
|
Assertion |
mhm0 |
|
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
mhm0.z |
|
| 2 |
|
mhm0.y |
|
| 3 |
|
eqid |
|
| 4 |
|
eqid |
|
| 5 |
|
eqid |
|
| 6 |
|
eqid |
|
| 7 |
3 4 5 6 1 2
|
ismhm |
|
| 8 |
7
|
simprbi |
|
| 9 |
8
|
simp3d |
|