Description: The additive neutral element of a division ring extension. (Contributed by Thierry Arnoux, 17-Jul-2023)
Ref | Expression | ||
---|---|---|---|
Hypotheses | drgext.b | |
|
drgext.1 | |
||
drgext.2 | |
||
Assertion | drgext0g | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | drgext.b | |
|
2 | drgext.1 | |
|
3 | drgext.2 | |
|
4 | 1 | a1i | |
5 | eqidd | |
|
6 | eqid | |
|
7 | 6 | subrgss | |
8 | 3 7 | syl | |
9 | 4 5 8 | sralmod0 | |