Definition df-oprab 7412

Description: Define the class abstraction (class builder) of a collection of nested ordered pairs (for use in defining operations). This is a special case of Definition 4.16 of [TakeutiZaring] p. 14. Normally 𝑥, 𝑦, and 𝑧 are distinct, although the definition doesn't strictly require it. See df-ov 7411 for the value of an operation. The brace notation is called "class abstraction" by Quine; it is also called a "class builder" in the literature. The value of an operation given by a class abstraction is given by ovmpo 7568. (Contributed by NM, 12-Mar-1995.)

Assertion

Ref	Expression
df-oprab	⊢ {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜑} = {𝑤 ∣ ∃𝑥∃𝑦∃𝑧(𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∧ 𝜑)}

Distinct variable groups:   𝑥,𝑤   𝑦,𝑤   𝑧,𝑤   𝜑,𝑤

Allowed substitution hints:   𝜑(𝑥, 𝑦, 𝑧)

Detailed syntax breakdown of Definition df-oprab

Step	Hyp	Ref	Expression
1		wph	. . 3 wff 𝜑
2		vx	. . 3 setvar 𝑥
3		vy	. . 3 setvar 𝑦
4		vz	. . 3 setvar 𝑧
5	1, 2, 3, 4	coprab 7409	. 2 class {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜑}
6		vw	. . . . . . . . 9 setvar 𝑤
7	6	cv 1569	. . . . . . . 8 class 𝑤
8	2	cv 1569	. . . . . . . . . 10 class 𝑥
9	3	cv 1569	. . . . . . . . . 10 class 𝑦
10	8, 9	cop 4589	. . . . . . . . 9 class ⟨𝑥, 𝑦⟩
11	4	cv 1569	. . . . . . . . 9 class 𝑧
12	10, 11	cop 4589	. . . . . . . 8 class ⟨⟨𝑥, 𝑦⟩, 𝑧⟩
13	7, 12	wceq 1570	. . . . . . 7 wff 𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩
14	13, 1	wa 401	. . . . . 6 wff (𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∧ 𝜑)
15	14, 4	wex 1812	. . . . 5 wff ∃𝑧(𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∧ 𝜑)
16	15, 3	wex 1812	. . . 4 wff ∃𝑦∃𝑧(𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∧ 𝜑)
17	16, 2	wex 1812	. . 3 wff ∃𝑥∃𝑦∃𝑧(𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∧ 𝜑)
18	17, 6	cab 2738	. 2 class {𝑤 ∣ ∃𝑥∃𝑦∃𝑧(𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∧ 𝜑)}
19	5, 18	wceq 1570	1 wff {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜑} = {𝑤 ∣ ∃𝑥∃𝑦∃𝑧(𝑤 = ⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∧ 𝜑)}

This definition is used by:  oprabidw  7439  oprabid  7440  dfoprab2  7466  nfoprab1  7469  nfoprab2  7470  nfoprab3  7471  nfoprab  7472  oprabbid  7473  oprabbidv  7474  ssoprab2  7476  0mpo0  7491  mpo0  7493  cbvoprab2  7496  cbvoprab12v  7498  cbvoprab3v  7500  eloprabga  7517  oprabrexex2  7973  eloprabi  8057  dftpos3  8239  join0  18538  meet0  18539  mppspstlem  36257  mppsval  36258  colinearex  36747  cbvoprab1vw  36948  cbvoprab2vw  36949  cbvoprab123vw  36950  cbvoprab23vw  36951  cbvoprab13vw  36952  cbvoprab1davw  36982  cbvoprab2davw  36983  cbvoprab3davw  36984  cbvoprab123davw  36985  cbvoprab12davw  36986  cbvoprab23davw  36987  cbvoprab13davw  36988  csboprabg  38173  eloprab1st2nd  49900