Description: The empty-coset of a class is the empty set. (Contributed by Peter Mazsa, 19-May-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | ec0 | ⊢ [ 𝐴 ] ∅ = ∅ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-ec | ⊢ [ 𝐴 ] ∅ = ( ∅ “ { 𝐴 } ) | |
2 | 0ima | ⊢ ( ∅ “ { 𝐴 } ) = ∅ | |
3 | 1 2 | eqtri | ⊢ [ 𝐴 ] ∅ = ∅ |