Metamath Proof Explorer
Description: Addition operation of an opposite ring. (Contributed by Mario
Carneiro, 1-Dec-2014)
|
|
Ref |
Expression |
|
Hypotheses |
opprbas.1 |
|
|
|
oppradd.2 |
|
|
Assertion |
oppradd |
|
Proof
Step |
Hyp |
Ref |
Expression |
1 |
|
opprbas.1 |
|
2 |
|
oppradd.2 |
|
3 |
|
df-plusg |
|
4 |
|
2nn |
|
5 |
|
2lt3 |
|
6 |
1 3 4 5
|
opprlem |
|
7 |
2 6
|
eqtri |
|