Transitive nonpropelinear perfect codes

Abstract: A code is called transitive if its automorphism group (the isometry group) of the code acts transitively on its codewords. If there is a subgroup of the automorphism group acting regularly on the code, the code is called propelinear. Using Magma software package we establish that among 201 equivalence classes of transitive perfect codes of length 15 from \cite{ost} there is a unique nonpropelinear code. We solve the existence problem for transitive nonpropelinear perfect codes for any admissible length $n$, $n\geq 15$. Moreover we prove that there are at least 5 pairwise nonequivalent such codes for any admissible length $n$, $n\geq 255$.