Description: Adding a second quantifier is a tranparent operation, ( A. A. case). (Contributed by BJ, 20-Oct-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | bj-alalbial | |- ( A. x A. x ph <-> A. x ph ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nfa1 | |- F/ x A. x ph |
|
2 | 1 | 19.3 | |- ( A. x A. x ph <-> A. x ph ) |