Description: Membership in an earlier upper set of integers. (Contributed by Paul Chapman, 22-Nov-2007) (Proof shortened by SN, 7-Feb-2025)
Ref | Expression | ||
---|---|---|---|
Hypotheses | eluzsubi.1 | |
|
eluzsubi.2 | |
||
Assertion | eluzsubi | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eluzsubi.1 | |
|
2 | eluzsubi.2 | |
|
3 | eluzsub | |
|
4 | 1 2 3 | mp3an12 | |