Metamath Proof Explorer


Theorem ressbasssOLD

Description: Obsolete version of ressbas as of 25-Feb-2025. (Contributed by Stefan O'Rear, 27-Nov-2014) (Revised by Mario Carneiro, 30-Apr-2015) (New usage is discouraged.) (Proof modification is discouraged.)

Ref Expression
Hypotheses ressbas.r ⊢ R = W ↾ 𝑠 A
ressbas.b ⊢ B = Base W
Assertion ressbasssOLD ⊢ Base R ⊆ B

Proof

Step Hyp Ref Expression
1 ressbas.r ⊢ R = W ↾ 𝑠 A
2 ressbas.b ⊢ B = Base W
3 1 2 ressbas ⊢ A ∈ V → A ∩ B = Base R
4 inss2 ⊢ A ∩ B ⊆ B
5 3 4 eqsstrrdi ⊢ A ∈ V → Base R ⊆ B
6 reldmress ⊢ Rel ⁡ dom ⁡ ↾ 𝑠
7 6 ovprc2 ⊢ ¬ A ∈ V → W ↾ 𝑠 A = ∅
8 1 7 eqtrid ⊢ ¬ A ∈ V → R = ∅
9 8 fveq2d ⊢ ¬ A ∈ V → Base R = Base ∅
10 base0 ⊢ ∅ = Base ∅
11 0ss ⊢ ∅ ⊆ B
12 10 11 eqsstrri ⊢ Base ∅ ⊆ B
13 9 12 eqsstrdi ⊢ ¬ A ∈ V → Base R ⊆ B
14 5 13 pm2.61i ⊢ Base R ⊆ B