Metamath Proof Explorer


Theorem dmovnsal

Description: The domain of the Lebesgue measure is a sigma-algebra. (Contributed by Glauco Siliprandi, 24-Dec-2020)

Ref Expression
Hypotheses dmovnsal.x ⊢ φ → X ∈ Fin
dmovnsal.s ⊢ S = dom ⁡ voln ⁡ X
Assertion dmovnsal ⊢ φ → S ∈ SAlg

Proof

Step Hyp Ref Expression
1 dmovnsal.x ⊢ φ → X ∈ Fin
2 dmovnsal.s ⊢ S = dom ⁡ voln ⁡ X
3 1 vonmea ⊢ φ → voln ⁡ X ∈ Meas
4 3 2 dmmeasal ⊢ φ → S ∈ SAlg