Section of an ordered set
cosmos
11th October 2017 at 3:31pm
(
−
∞
,
a
)
=
{
x
∈
X
∣
x
<
a
}
(-\infty, a) = \{x \in X | x < a\}
(
−
∞
,
a
)
=
{
x
∈
X
∣
x
<
a
}
Like a half-
Open interval