Description: Lemma for fin23 . X is either contained in or disjoint from all input sets. (Contributed by Stefan O'Rear, 1-Nov-2014)
Ref | Expression | ||
---|---|---|---|
Hypothesis | fin23lem.a | |
|
Assertion | fin23lem20 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fin23lem.a | |
|
2 | 1 | fnseqom | |
3 | peano2 | |
|
4 | fnfvelrn | |
|
5 | 2 3 4 | sylancr | |
6 | intss1 | |
|
7 | 5 6 | syl | |
8 | 1 | fin23lem19 | |
9 | sstr2 | |
|
10 | ssdisj | |
|
11 | 10 | ex | |
12 | 9 11 | orim12d | |
13 | 7 8 12 | sylc | |