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Description: The center of a group is an abelian group. (Contributed by Thierry Arnoux, 21-Aug-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | cntrcmnd.z | |- Z = ( M |`s ( Cntr ` M ) ) |
|
| Assertion | cntrabl | |- ( M e. Grp -> Z e. Abel ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cntrcmnd.z | |- Z = ( M |`s ( Cntr ` M ) ) |
|
| 2 | eqid | |- ( Base ` M ) = ( Base ` M ) |
|
| 3 | eqid | |- ( Cntz ` M ) = ( Cntz ` M ) |
|
| 4 | 2 3 | cntrval | |- ( ( Cntz ` M ) ` ( Base ` M ) ) = ( Cntr ` M ) |
| 5 | ssid | |- ( Base ` M ) C_ ( Base ` M ) |
|
| 6 | 2 3 | cntzsubg | |- ( ( M e. Grp /\ ( Base ` M ) C_ ( Base ` M ) ) -> ( ( Cntz ` M ) ` ( Base ` M ) ) e. ( SubGrp ` M ) ) |
| 7 | 5 6 | mpan2 | |- ( M e. Grp -> ( ( Cntz ` M ) ` ( Base ` M ) ) e. ( SubGrp ` M ) ) |
| 8 | 4 7 | eqeltrrid | |- ( M e. Grp -> ( Cntr ` M ) e. ( SubGrp ` M ) ) |
| 9 | 1 | subggrp | |- ( ( Cntr ` M ) e. ( SubGrp ` M ) -> Z e. Grp ) |
| 10 | 8 9 | syl | |- ( M e. Grp -> Z e. Grp ) |
| 11 | grpmnd | |- ( M e. Grp -> M e. Mnd ) |
|
| 12 | 1 | cntrcmnd | |- ( M e. Mnd -> Z e. CMnd ) |
| 13 | 11 12 | syl | |- ( M e. Grp -> Z e. CMnd ) |
| 14 | isabl | |- ( Z e. Abel <-> ( Z e. Grp /\ Z e. CMnd ) ) |
|
| 15 | 10 13 14 | sylanbrc | |- ( M e. Grp -> Z e. Abel ) |