Description: Lemma for isfin3-2 . Being a chain, difference sets are disjoint. (Contributed by Stefan O'Rear, 5-Nov-2014)
Ref | Expression | ||
---|---|---|---|
Hypotheses | isf32lem.a | |
|
isf32lem.b | |
||
isf32lem.c | |
||
Assertion | isf32lem4 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | isf32lem.a | |
|
2 | isf32lem.b | |
|
3 | isf32lem.c | |
|
4 | simplrr | |
|
5 | simplrl | |
|
6 | simpr | |
|
7 | simplll | |
|
8 | incom | |
|
9 | 1 2 3 | isf32lem3 | |
10 | 8 9 | eqtrid | |
11 | 4 5 6 7 10 | syl22anc | |
12 | simplrl | |
|
13 | simplrr | |
|
14 | simpr | |
|
15 | simplll | |
|
16 | 1 2 3 | isf32lem3 | |
17 | 12 13 14 15 16 | syl22anc | |
18 | simplr | |
|
19 | nnord | |
|
20 | nnord | |
|
21 | ordtri3 | |
|
22 | 19 20 21 | syl2an | |
23 | 22 | adantl | |
24 | 23 | necon2abid | |
25 | 18 24 | mpbird | |
26 | 11 17 25 | mpjaodan | |