Description: Obsolete version of issgrp as of 3-Feb-2020. The predicate "is a semigroup". (Contributed by FL, 2-Nov-2009) (New usage is discouraged.) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypothesis | issmgrpOLD.1 | |
|
Assertion | issmgrpOLD | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | issmgrpOLD.1 | |
|
2 | df-sgrOLD | |
|
3 | 2 | eleq2i | |
4 | elin | |
|
5 | 1 | ismgmOLD | |
6 | 1 | isass | |
7 | 5 6 | anbi12d | |
8 | 4 7 | syl5bb | |
9 | 3 8 | syl5bb | |