| Metamath Proof Explorer |
< Previous
Next >
Related theorems Unicode version |
| Description: Expansion of membership in an intersection of two classes. Theorem 12 of [Suppes] p. 25. |
| Ref | Expression |
|---|---|
| elin |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elisset 2299 |
. 2
| |
| 2 | elisset 2299 |
. . 3
| |
| 3 | 2 | adantl 424 |
. 2
|
| 4 | eleq1 1957 |
. . . 4
| |
| 5 | eleq1 1957 |
. . . 4
| |
| 6 | 4, 5 | anbi12d 690 |
. . 3
|
| 7 | df-in 2603 |
. . 3
| |
| 8 | 6, 7 | elab2g 2406 |
. 2
|
| 9 | 1, 3, 8 | pm5.21nii 743 |
1
|