A. GRYTCZUK
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135
X joined in G to an odd number of vertices in
or there exists
Y
Y joined in G to an odd number of
vertices in
.
Cremona-Odoni Theorem: [1] If n and
dD
d
,
is an odd graph then is negative Pellian.
d
Remark: If the Diophantine equation
has a solution in positive integers
22
xd=1y
y
then the number is called as negative Pellian.
d
From this Remark, Theorem 2 and The Cremona-
Odoni theorem it follows the following Corollary:
Corollary 2: If and ,
n
dDn2
d is an odd
graph, then
>1.hd
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