Metamath Proof Explorer


Theorem bnj222

Description: Technical lemma for bnj229 . This lemma may no longer be used or have become an indirect lemma of the theorem in question (i.e. a lemma of a lemma... of the theorem). (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypothesis bnj222.1 ⊢ ψ ↔ ∀ i ∈ ω suc ⁡ i ∈ N → F ⁡ suc ⁡ i = ⋃ y ∈ F ⁡ i pred y A R
Assertion bnj222 ⊢ ψ ↔ ∀ m ∈ ω suc ⁡ m ∈ N → F ⁡ suc ⁡ m = ⋃ y ∈ F ⁡ m pred y A R

Proof

Step Hyp Ref Expression
1 bnj222.1 ⊢ ψ ↔ ∀ i ∈ ω suc ⁡ i ∈ N → F ⁡ suc ⁡ i = ⋃ y ∈ F ⁡ i pred y A R
2 suceq ⊢ i = m → suc ⁡ i = suc ⁡ m
3 2 eleq1d ⊢ i = m → suc ⁡ i ∈ N ↔ suc ⁡ m ∈ N
4 2 fveq2d ⊢ i = m → F ⁡ suc ⁡ i = F ⁡ suc ⁡ m
5 fveq2 ⊢ i = m → F ⁡ i = F ⁡ m
6 5 bnj1113 ⊢ i = m → ⋃ y ∈ F ⁡ i pred y A R = ⋃ y ∈ F ⁡ m pred y A R
7 4 6 eqeq12d ⊢ i = m → F ⁡ suc ⁡ i = ⋃ y ∈ F ⁡ i pred y A R ↔ F ⁡ suc ⁡ m = ⋃ y ∈ F ⁡ m pred y A R
8 3 7 imbi12d ⊢ i = m → suc ⁡ i ∈ N → F ⁡ suc ⁡ i = ⋃ y ∈ F ⁡ i pred y A R ↔ suc ⁡ m ∈ N → F ⁡ suc ⁡ m = ⋃ y ∈ F ⁡ m pred y A R
9 8 cbvralvw ⊢ ∀ i ∈ ω suc ⁡ i ∈ N → F ⁡ suc ⁡ i = ⋃ y ∈ F ⁡ i pred y A R ↔ ∀ m ∈ ω suc ⁡ m ∈ N → F ⁡ suc ⁡ m = ⋃ y ∈ F ⁡ m pred y A R
10 1 9 bitri ⊢ ψ ↔ ∀ m ∈ ω suc ⁡ m ∈ N → F ⁡ suc ⁡ m = ⋃ y ∈ F ⁡ m pred y A R