Definition df-igam 26988

Description: Define the inverse Gamma function, which is defined everywhere, unlike the Gamma function itself. (Contributed by Mario Carneiro, 16-Jul-2017.)

Assertion

Ref	Expression
df-igam	⊢ 1/Γ = (𝑥 ∈ ℂ ↦ if(𝑥 ∈ (ℤ ∖ ℕ), 0, (1 / (Γ‘𝑥))))

Detailed syntax breakdown of Definition df-igam

Step	Hyp	Ref	Expression
1		cigam 26985	. 2 class 1/Γ
2		vx	. . 3 setvar 𝑥
3		cc 11132	. . 3 class ℂ
4	2	cv 1539	. . . . 5 class 𝑥
5		cz 12593	. . . . . 6 class ℤ
6		cn 12245	. . . . . 6 class ℕ
7	5, 6	cdif 3928	. . . . 5 class (ℤ ∖ ℕ)
8	4, 7	wcel 2109	. . . 4 wff 𝑥 ∈ (ℤ ∖ ℕ)
9		cc0 11134	. . . 4 class 0
10		c1 11135	. . . . 5 class 1
11		cgam 26984	. . . . . 6 class Γ
12	4, 11	cfv 6536	. . . . 5 class (Γ‘𝑥)
13		cdiv 11899	. . . . 5 class /
14	10, 12, 13	co 7410	. . . 4 class (1 / (Γ‘𝑥))
15	8, 9, 14	cif 4505	. . 3 class if(𝑥 ∈ (ℤ ∖ ℕ), 0, (1 / (Γ‘𝑥)))
16	2, 3, 15	cmpt 5206	. 2 class (𝑥 ∈ ℂ ↦ if(𝑥 ∈ (ℤ ∖ ℕ), 0, (1 / (Γ‘𝑥))))
17	1, 16	wceq 1540	1 wff 1/Γ = (𝑥 ∈ ℂ ↦ if(𝑥 ∈ (ℤ ∖ ℕ), 0, (1 / (Γ‘𝑥))))

This definition is referenced by:  igamval  27014  igamf  27018