Description: Subtraction in a ring, in terms of addition and negation. (Contributed by Jeff Madsen, 19-Jun-2010)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ringnegcl.1 | ||
| ringnegcl.2 | |||
| ringnegcl.3 | |||
| ringsub.4 | |||
| Assertion | rngosub |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ringnegcl.1 | ||
| 2 | ringnegcl.2 | ||
| 3 | ringnegcl.3 | ||
| 4 | ringsub.4 | ||
| 5 | 1 | rngogrpo | |
| 6 | 2 3 4 | grpodivval | |
| 7 | 5 6 | syl3an1 |