Definition df-dde 29623

Description: Define the Dirac delta measure. (Contributed by Thierry Arnoux, 14-Sep-2018.)

Assertion

Ref	Expression
df-dde	⊢ δ = (𝑎 ∈ 𝒫 ℝ ↦ if(0 ∈ 𝑎, 1, 0))

Detailed syntax breakdown of Definition df-dde

Step	Hyp	Ref	Expression
1		cdde 29622	. 2 class δ
2		va	. . 3 setvar 𝑎
3		cr 9814	. . . 4 class ℝ
4	3	cpw 4108	. . 3 class 𝒫 ℝ
5		cc0 9815	. . . . 5 class 0
6	2	cv 1474	. . . . 5 class 𝑎
7	5, 6	wcel 1977	. . . 4 wff 0 ∈ 𝑎
8		c1 9816	. . . 4 class 1
9	7, 8, 5	cif 4036	. . 3 class if(0 ∈ 𝑎, 1, 0)
10	2, 4, 9	cmpt 4643	. 2 class (𝑎 ∈ 𝒫 ℝ ↦ if(0 ∈ 𝑎, 1, 0))
11	1, 10	wceq 1475	1 wff δ = (𝑎 ∈ 𝒫 ℝ ↦ if(0 ∈ 𝑎, 1, 0))

This definition is referenced by:  ddeval1  29624  ddeval0  29625  ddemeas  29626