Metamath Proof Explorer


Theorem itg2lr

Description: Sufficient condition for elementhood in the set L . (Contributed by Mario Carneiro, 28-Jun-2014)

Ref Expression
Hypothesis itg2val.1 ⊢ L = x | ∃ g ∈ dom ⁡ ∫ 1 g ≤ f F ∧ x = ∫ 1 ⁡ g
Assertion itg2lr ⊢ G ∈ dom ⁡ ∫ 1 ∧ G ≤ f F → ∫ 1 ⁡ G ∈ L

Proof

Step Hyp Ref Expression
1 itg2val.1 ⊢ L = x | ∃ g ∈ dom ⁡ ∫ 1 g ≤ f F ∧ x = ∫ 1 ⁡ g
2 eqid ⊢ ∫ 1 ⁡ G = ∫ 1 ⁡ G
3 breq1 ⊢ g = G → g ≤ f F ↔ G ≤ f F
4 fveq2 ⊢ g = G → ∫ 1 ⁡ g = ∫ 1 ⁡ G
5 4 eqeq2d ⊢ g = G → ∫ 1 ⁡ G = ∫ 1 ⁡ g ↔ ∫ 1 ⁡ G = ∫ 1 ⁡ G
6 3 5 anbi12d ⊢ g = G → g ≤ f F ∧ ∫ 1 ⁡ G = ∫ 1 ⁡ g ↔ G ≤ f F ∧ ∫ 1 ⁡ G = ∫ 1 ⁡ G
7 6 rspcev ⊢ G ∈ dom ⁡ ∫ 1 ∧ G ≤ f F ∧ ∫ 1 ⁡ G = ∫ 1 ⁡ G → ∃ g ∈ dom ⁡ ∫ 1 g ≤ f F ∧ ∫ 1 ⁡ G = ∫ 1 ⁡ g
8 2 7 mpanr2 ⊢ G ∈ dom ⁡ ∫ 1 ∧ G ≤ f F → ∃ g ∈ dom ⁡ ∫ 1 g ≤ f F ∧ ∫ 1 ⁡ G = ∫ 1 ⁡ g
9 1 itg2l ⊢ ∫ 1 ⁡ G ∈ L ↔ ∃ g ∈ dom ⁡ ∫ 1 g ≤ f F ∧ ∫ 1 ⁡ G = ∫ 1 ⁡ g
10 8 9 sylibr ⊢ G ∈ dom ⁡ ∫ 1 ∧ G ≤ f F → ∫ 1 ⁡ G ∈ L