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Characterizations of Left and Right Exactness in Abelian Categories
category-theory
Author
sun123zxy
Published
October 11, 2026
colim
I
⊣
∆
⊣
lim
I
left
adjoin
t
righ
t
adjoin
t
preserv
es
colimits
preserv
es
limits
preserv
e
fnite
colimits
preserv
e
fnite
limits
preserv
e
cok
ernels
preserv
e
k
ernels
righ
t
exact
left
exact
exact
assumptions:
ab
elian
category
additiv
e
functor
small
(co)limits
colim
I
is
lim
I
is
+
I
fltered
/
discrete
+
R
Mod
(AB5)
colim
I
is
+
I
discrete
+
R
Mod
(AB4*)
lim
I
is
+
p
erserv
e
direct
sums
+
preserv
e
direct
pro
ducts
Figure 1