Post your solutions to the Jan 29 In-class Exercise to this thread.
Chris
∃x,y ( x∈A ∧ y∈A ∧ x=/=y ∧ A={x,y} )
∃ x, y x =/= y, A =/= {} A ∪ {x, y} = {x, y} A ∩ {x, y} = {x, y}
A={x,y}, x=/=y ∧ A∈{x, y} ∧ {x, y}∈A
( x ∈ A ) ∧ ( y ∈ A ) ∧ ( x =/= y ) ∧ ( A = {x, y})
∃ x,y ( x ∈ A ∧ y ∈ A ∧ x ≠ y ∧ A = {x,y} )
∈ = element of , ∃ = exists , ∧ = And
(Edited: 2020-02-02)∃x,y ( x ∈ A ^ y ∈ A ^ x ≠ y ^ A = {x,y} )
∃ x,y (x ∈ A ∧ y ∈ A ∧ x ≠ y ∧ (¬∃ z (z ∈ A ⇒ z ≠ x ∧ z ≠ y)))