theorem alleq2d (_G: wff) (A: set) (_l1 _l2: nat): $ _G -> _l1 = _l2 $ > $ _G -> (all A _l1 <-> all A _l2) $;
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqsidd | _G -> A == A |
|
2 | hyp _h | _G -> _l1 = _l2 |
|
3 | 1, 2 | alleqd | _G -> (all A _l1 <-> all A _l2) |