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An upper bound on the Chebotarev invariant of a finite group
A subset { g 1 ,..., g d } of a finite group G invariably generates { g 1 x 1 , ... , g d x d } generates G for every choice of x i ∈ G . The Chebotarev invariant C ( G ) of G is the expected value of the random variable n that is minimal subject to the requirement that n randomly chosen elements of...
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Published in: | Israel journal of mathematics 2017-04, Vol.219 (1), p.449-467 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | A subset {
g
1
,...,
g
d
} of a finite group
G
invariably generates
{
g
1
x
1
,
...
,
g
d
x
d
}
generates
G
for every choice of
x
i
∈
G
. The Chebotarev invariant
C
(
G
) of
G
is the expected value of the random variable
n
that is minimal subject to the requirement that
n
randomly chosen elements of
G
invariably generate
G
. The first author recently showed that
C
(
G
)
≤
β
|
G
|
for some absolute constant
β
. In this paper we show that, when G is soluble, then
β
is at most 5/3. We also show that this is best possible. Furthermore, we show that, in general, for each ε > 0 there exists a constant
c
ε
such that
C
(
G
)
≤
(
1
+
∈
)
|
G
|
+
c
∈
. |
---|---|
ISSN: | 0021-2172 1565-8511 |
DOI: | 10.1007/s11856-017-1507-x |