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Definition df-ssetk 4193
 Description: Define the Kuratowski subset relationship. (Contributed by SF, 12-Jan-2015.)
Assertion
Ref Expression
df-ssetk Sk = {x yz(x = ⟪y, z y z)}
Distinct variable group:   x,y,z

Detailed syntax breakdown of Definition df-ssetk
StepHypRef Expression
1 cssetk 4183 . 2 class Sk
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
105, 7wss 3257 . . . . . 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 Sk = {x yz(x = ⟪y, z y z)}
 Colors of variables: wff setvar class This definition is referenced by:  opkelssetkg  4268  ssetkssvvk  4278
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