Description: Subset law for projective subspace sum. ( unss2 analog.) (Contributed by NM, 7-Mar-2012)
Ref | Expression | ||
---|---|---|---|
Hypotheses | padd0.a | |
|
padd0.p | |
||
Assertion | paddss2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | padd0.a | |
|
2 | padd0.p | |
|
3 | ssel | |
|
4 | 3 | orim2d | |
5 | ssrexv | |
|
6 | 5 | reximdv | |
7 | 6 | anim2d | |
8 | 4 7 | orim12d | |
9 | 8 | adantl | |
10 | simpl1 | |
|
11 | simpl3 | |
|
12 | sstr | |
|
13 | 12 | 3ad2antr2 | |
14 | 13 | ancoms | |
15 | eqid | |
|
16 | eqid | |
|
17 | 15 16 1 2 | elpadd | |
18 | 10 11 14 17 | syl3anc | |
19 | simpl2 | |
|
20 | 15 16 1 2 | elpadd | |
21 | 10 11 19 20 | syl3anc | |
22 | 9 18 21 | 3imtr4d | |
23 | 22 | ssrdv | |
24 | 23 | ex | |