Description: The zero of a unital ring is a left-absorbing element. (Contributed by FL, 31-Aug-2009) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypotheses | ringlz.1 | |
|
ringlz.2 | |
||
ringlz.3 | |
||
ringlz.4 | |
||
Assertion | rngolz | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ringlz.1 | |
|
2 | ringlz.2 | |
|
3 | ringlz.3 | |
|
4 | ringlz.4 | |
|
5 | 3 | rngogrpo | |
6 | 2 1 | grpoidcl | |
7 | 2 1 | grpolid | |
8 | 5 6 7 | syl2anc2 | |
9 | 8 | adantr | |
10 | 9 | oveq1d | |
11 | 3 2 1 | rngo0cl | |
12 | 11 | adantr | |
13 | simpr | |
|
14 | 12 12 13 | 3jca | |
15 | 3 4 2 | rngodir | |
16 | 14 15 | syldan | |
17 | 5 | adantr | |
18 | simpl | |
|
19 | 3 4 2 | rngocl | |
20 | 18 12 13 19 | syl3anc | |
21 | 2 1 | grporid | |
22 | 21 | eqcomd | |
23 | 17 20 22 | syl2anc | |
24 | 10 16 23 | 3eqtr3d | |
25 | 2 | grpolcan | |
26 | 17 20 12 20 25 | syl13anc | |
27 | 24 26 | mpbid | |