On $k$-transitivity conditions of a product of regular permutation groups
A. V. Toktarev Lomonosov Moscow State University
Abstract:
The paper analyses the product of
$m$ regular permutation groups
${G_1}\cdot\ldots\cdot{G_{m}}$, where
$m \geq 2 $ is natural number. Each of regular permutation groups is the subgroup of symmetric permutation group
$S(\Omega)$ of degree
$|\Omega|$ for the set
$\Omega$. M. M. Glukhov proved that for
$k=2$ and
$m=2$,
$2$-transitivity of the product
${G_1}\cdot{G_{2}}$ is equivalent to the absence of zeros in the corresponding square matrix with number of rows and columns equal to
$|\Omega|-1$. Also by M. M. Glukhov necessary conditions of
$2$-transitivity of such product of regular permutation groups are given.
In this paper, we consider the general case for any natural
$m$ and
$k$ such that
$m \geq 2 $ and
$k \geq 2 $. It is proved that
$k$-transitivity of product of regular permutation groups
${G_1}\cdot\ldots\cdot{G_{m}}$ is equivalent to the absence of zeros in the square matrix with number of rows and columns equal to
$(|\Omega | - 1)!/(|\Omega | - k)!$. We obtain correlation between the number of arcs corresponding to this matrix and a natural number
$ l $ such that the product
$(PsQt)^{l}$ is
$2$-transitive, where
$P,Q \subseteq S(\Omega )$ are some regular permutation groups and permutation
$st$ is
$(|\Omega | - 1)$-loop. We provide an example of the building of AES ciphers such that their round transformation are
$ k $-transitive on a number of rounds.
UDC:
512.542.72