Description: Commutation of restricted existential quantifiers. (Contributed by NM, 19-Nov-1995) (Revised by Mario Carneiro, 14-Oct-2016) (Proof shortened by BJ, 26-Aug-2023) (Proof shortened by Wolf Lammen, 8-Dec-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | rexcom | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ralcom | |
|
2 | ralnex2 | |
|
3 | ralnex2 | |
|
4 | 1 2 3 | 3bitr3i | |
5 | 4 | con4bii | |