Metamath Proof Explorer


Theorem paddss2

Description: Subset law for projective subspace sum. ( unss2 analog.) (Contributed by NM, 7-Mar-2012)

Ref Expression
Hypotheses padd0.a A=AtomsK
padd0.p +˙=+𝑃K
Assertion paddss2 KBYAZAXYZ+˙XZ+˙Y

Proof

Step Hyp Ref Expression
1 padd0.a A=AtomsK
2 padd0.p +˙=+𝑃K
3 ssel XYpXpY
4 3 orim2d XYpZpXpZpY
5 ssrexv XYrXpKqjoinKrrYpKqjoinKr
6 5 reximdv XYqZrXpKqjoinKrqZrYpKqjoinKr
7 6 anim2d XYpAqZrXpKqjoinKrpAqZrYpKqjoinKr
8 4 7 orim12d XYpZpXpAqZrXpKqjoinKrpZpYpAqZrYpKqjoinKr
9 8 adantl KBYAZAXYpZpXpAqZrXpKqjoinKrpZpYpAqZrYpKqjoinKr
10 simpl1 KBYAZAXYKB
11 simpl3 KBYAZAXYZA
12 sstr XYYAXA
13 12 3ad2antr2 XYKBYAZAXA
14 13 ancoms KBYAZAXYXA
15 eqid K=K
16 eqid joinK=joinK
17 15 16 1 2 elpadd KBZAXApZ+˙XpZpXpAqZrXpKqjoinKr
18 10 11 14 17 syl3anc KBYAZAXYpZ+˙XpZpXpAqZrXpKqjoinKr
19 simpl2 KBYAZAXYYA
20 15 16 1 2 elpadd KBZAYApZ+˙YpZpYpAqZrYpKqjoinKr
21 10 11 19 20 syl3anc KBYAZAXYpZ+˙YpZpYpAqZrYpKqjoinKr
22 9 18 21 3imtr4d KBYAZAXYpZ+˙XpZ+˙Y
23 22 ssrdv KBYAZAXYZ+˙XZ+˙Y
24 23 ex KBYAZAXYZ+˙XZ+˙Y