Description: Relation of the inclusion poset. (Contributed by Stefan O'Rear, 30-Jan-2015)
Ref | Expression | ||
---|---|---|---|
Hypothesis | ipoval.i | |
|
Assertion | ipolerval | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ipoval.i | |
|
2 | simpl | |
|
3 | vex | |
|
4 | vex | |
|
5 | 3 4 | prss | |
6 | 2 5 | sylibr | |
7 | 6 | ssopab2i | |
8 | df-xp | |
|
9 | 7 8 | sseqtrri | |
10 | sqxpexg | |
|
11 | ssexg | |
|
12 | 9 10 11 | sylancr | |
13 | ipostr | |
|
14 | pleid | |
|
15 | snsspr1 | |
|
16 | ssun2 | |
|
17 | 15 16 | sstri | |
18 | 13 14 17 | strfv | |
19 | 12 18 | syl | |
20 | eqid | |
|
21 | 1 20 | ipoval | |
22 | 21 | fveq2d | |
23 | 19 22 | eqtr4d | |