Metamath Proof Explorer


Theorem nn0xnn0d

Description: A standard nonnegative integer is an extended nonnegative integer, deduction form. (Contributed by AV, 10-Dec-2020)

Ref Expression
Hypothesis nn0xnn0d.1 ( 𝜑𝐴 ∈ ℕ0 )
Assertion nn0xnn0d ( 𝜑𝐴 ∈ ℕ0* )

Proof

Step Hyp Ref Expression
1 nn0xnn0d.1 ( 𝜑𝐴 ∈ ℕ0 )
2 nn0ssxnn0 0 ⊆ ℕ0*
3 2 1 sseldi ( 𝜑𝐴 ∈ ℕ0* )