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Definition df-idk 4195
 Description: Define the Kuratowski identity relationship. (Contributed by SF, 12-Jan-2015.)
Assertion
Ref Expression
df-idk Ik = {x yz(x = ⟪y, z y = z)}
Distinct variable group:   x,y,z

Detailed syntax breakdown of Definition df-idk
StepHypRef Expression
1 cidk 4184 . 2 class Ik
2 vx . . . . . . . 8 setvar x
32cv 1641 . . . . . . 7 class x
4 vy . . . . . . . . 9 setvar y
54cv 1641 . . . . . . . 8 class y
6 vz . . . . . . . . 9 setvar z
76cv 1641 . . . . . . . 8 class z
85, 7copk 4057 . . . . . . 7 class y, z
93, 8wceq 1642 . . . . . 6 wff x = ⟪y, z
104, 6weq 1643 . . . . . 6 wff y = z
119, 10wa 358 . . . . 5 wff (x = ⟪y, z y = z)
1211, 6wex 1541 . . . 4 wff z(x = ⟪y, z y = z)
1312, 4wex 1541 . . 3 wff yz(x = ⟪y, z y = z)
1413, 2cab 2339 . 2 class {x yz(x = ⟪y, z y = z)}
151, 14wceq 1642 1 wff Ik = {x yz(x = ⟪y, z y = z)}
 Colors of variables: wff setvar class This definition is referenced by:  opkelidkg  4274  idkssvvk  4281
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