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Grinberg-Introduction-Graph-Theory
· Problem 6.2
Colorings
Mathematics — Graph Theory · proper-2-colorings
Problem
Let
G
G
G
be a connected loopless multigraph. Prove that
G
G
G
has a proper 2-coloring if and only if every three vertices
u
,
v
,
w
u, v, w
u
,
v
,
w
of
G
G
G
satisfy
2
∣
d
(
u
,
v
)
+
d
(
v
,
w
)
+
d
(
w
,
u
)
.
2 \mid d(u,v) + d(v,w) + d(w,u).
2
∣
d
(
u
,
v
)
+
d
(
v
,
w
)
+
d
(
w
,
u
)
.
Related theory
Proper Time And Proper Length
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