Metamath Proof Explorer


Theorem coe1fval

Description: Value of the univariate polynomial coefficient function. (Contributed by Stefan O'Rear, 21-Mar-2015)

Ref Expression
Hypothesis coe1fval.a ⊢ A = coe 1 ⁡ F
Assertion coe1fval ⊢ F ∈ V → A = n ∈ ℕ 0 ⟼ F ⁡ 1 𝑜 × n

Proof

Step Hyp Ref Expression
1 coe1fval.a ⊢ A = coe 1 ⁡ F
2 elex ⊢ F ∈ V → F ∈ V
3 fveq1 ⊢ f = F → f ⁡ 1 𝑜 × n = F ⁡ 1 𝑜 × n
4 3 mpteq2dv ⊢ f = F → n ∈ ℕ 0 ⟼ f ⁡ 1 𝑜 × n = n ∈ ℕ 0 ⟼ F ⁡ 1 𝑜 × n
5 df-coe1 ⊢ coe 1 = f ∈ V ⟼ n ∈ ℕ 0 ⟼ f ⁡ 1 𝑜 × n
6 nn0ex ⊢ ℕ 0 ∈ V
7 6 mptex ⊢ n ∈ ℕ 0 ⟼ F ⁡ 1 𝑜 × n ∈ V
8 4 5 7 fvmpt ⊢ F ∈ V → coe 1 ⁡ F = n ∈ ℕ 0 ⟼ F ⁡ 1 𝑜 × n
9 1 8 eqtrid ⊢ F ∈ V → A = n ∈ ℕ 0 ⟼ F ⁡ 1 𝑜 × n
10 2 9 syl ⊢ F ∈ V → A = n ∈ ℕ 0 ⟼ F ⁡ 1 𝑜 × n