CoRN.util.Container
Require
Import
canonical_names
.
Class
Container
(
Elem
C
:
Type
) :=
In
:
C
→
Elem
→
Prop
.
Hint Unfold
In
.
Notation
"
x ∈ y" := (
In
y
x
) (
at
level
70).
Notation
"
x ∉ y" := (
¬
In
y
x
) (
at
level
70).
Notation
"
(∈ y )" := (
In
y
).