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The family of rings of the form \frac{\mathbb{Z}_{4}\left \langle x,y \right \rangle}{\left \langle x^2-a,y^2-b,yx-xy-2(c+dx+ey+fxy) \right \rangle} is investigated which contains the generalized Hamilton quaternions over $\Z_4$. These rings are local rings of order 256. This family has 256 rings contained in 88 distinct isomorphism classes. Of the 88 non-isomorphic rings, 10 are minimal reversible nonsymmetric rings and 21 are minimal abelian reflexive nonsemicommutative rings. Few such examples have been identified in the literature thus far. The computational methods used to identify the isomorphism classes are also highlighted. Finally, some generalized Hamilton quaternion rings over $\Z_{p^s}$ are characterized.

It has recently been shown that a minimal reversible nonsymmetric ring has order 256 answering a question originally posed in a paper on a taxonomy of 2-primal rings. In a different work, questions on minimal rings having to do with this taxonomy were also answered. In this work it is shown that a minimal abelian reflexive nonsemicommutative ring also has order 256, a related question left open in these previous works. It is also shown here that [Formula: see text] is such a minimal ring. This is a consequence of the main result of the paper which is that a finite abelian reflexive ring of order [Formula: see text] for some prime [Formula: see text] and [Formula: see text] is reversible.

Let [math] be a sequence of [math] pairwise coprime positive integers, [math] , and [math] be a sequence of [math] different colors. Let [math] be an [math] matrix of colors in which row [math] consists of blocks of [math] consecutive entries of the same color with colors 0 through [math] repeated cyclically. The monochromatic column problem is to determine the number of columns of [math] in which every entry is the same color. The solution for a prime number of colors is provided.

In this paper we study polycyclic codes of length $p^{s_1} \times \cdots \times p^{s_n}$\ over $\F_{p^a}$\ generated by a single monomial. These codes form a special class of abelian codes. We show that these codes arise from the product of certain single variable codes and we determine their minimum Hamming distance. Finally we extend the results of Massey et. al. in \cite{MASSEY_1973} on the weight retaining property of monomials in one variable to the weight retaining property of monomials in several variables.

Dual codes are defined with respect to non-degenerate sesquilinear or bilinear forms over a finite Frobenius ring. These dual codes have the properties one expects from a dual code: they satisfy a double-dual property, they have cardinality complementary to that of the primal code, and they satisfy the MacWilliams identities for the Hamming weight.

article number 1750161; International audience; Given a finite ring $A$ which is a free left module over a subring $R$ of $A$, two types of $R$-bases are defined which in turn are used to define duality preserving maps from codes over $A$ to codes over $R$. The first type, pseudo-self-dual bases, are a generalization of trace orthogonal bases for fields. The second are called symmetric bases. Both types are illustrated with skew cyclic codes which are codes that are $A$-submodules of the skew polynomial ring $A[X;\theta]/\langle X^n-1\rangle$ (the classical cyclic codes are the case when $\theta=id$). When $A$ is commutative, there exists criteria for a skew cyclic code over $A$ to be self-dual. With this criteria and a duality preserving map, many self-dual codes over the subring $R$ can easily be found. In this fashion, numerous examples are given, some of which are not chain or serial rings.

Phosphatidylinositol 3-kinases (PI3Ks) are lipid kinases that regulate signaling pathways important for neoplasia, including cell proliferation, adhesion, survival, and motility ([ 1 ][1]–[ 3 ][2]). To determine if PI3Ks are genetically altered in tumorigenesis, we sequenced PI3K genes in human