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Metamath Proof Explorer


Theorem funpartss

Description: The functional part of F is a subset of F . (Contributed by Scott Fenton, 17-Apr-2014) (Revised by Mario Carneiro, 19-Apr-2014)

Ref Expression
Assertion funpartss Funpart 𝐹𝐹

Proof

Step Hyp Ref Expression
1 df-funpart Funpart 𝐹 = ( 𝐹 ↾ dom ( ( Image 𝐹 ∘ Singleton ) ∩ ( V × Singletons ) ) )
2 resss ( 𝐹 ↾ dom ( ( Image 𝐹 ∘ Singleton ) ∩ ( V × Singletons ) ) ) ⊆ 𝐹
3 1 2 eqsstri Funpart 𝐹𝐹