Metamath Proof Explorer


Theorem fvilbdRP

Description: A set is a subset of its image under the identity relation. (Contributed by RP, 22-Jul-2020) (Proof modification is discouraged.)

Ref Expression
Hypothesis fvilbdRP.r ⊢ φ → R ∈ V
Assertion fvilbdRP ⊢ φ → R ⊆ I ⁡ R

Proof

Step Hyp Ref Expression
1 fvilbdRP.r ⊢ φ → R ∈ V
2 dfid6 ⊢ I = r ∈ V ⟼ ⋃ n ∈ 1 r ↑ r n
3 snex ⊢ 1 ∈ V
4 3 a1i ⊢ φ → 1 ∈ V
5 1ex ⊢ 1 ∈ V
6 5 snid ⊢ 1 ∈ 1
7 6 a1i ⊢ φ → 1 ∈ 1
8 2 1 4 7 fvmptiunrelexplb1d ⊢ φ → R ⊆ I ⁡ R