MathGloss
A
left ideal
of a
ring
R
R
R
is a subset
I
⊆
R
I\subseteq R
I
⊆
R
such that
(
I
,
+
)
(I,+)
(
I
,
+
)
is a
subgroup
of
(
R
,
+
)
(R,+)
(
R
,
+
)
;
I
I
I
is closed under left multiplication in
R
R
R
(i.e. for all
i
∈
R
i\in R
i
∈
R
and all
r
∈
R
r\in R
r
∈
R
,
r
i
∈
I
ri \in I
r
i
∈
I
).
Wikidata ID:
Q44649