"Matrix mappings preserving Diedonne determinant and their algorithmic constructions" Elena Kreines Department of Mechanics and Mathematics, Moscow State University. ABSTRACT. In this paper the following problem is considered: let $D$ be a skew-field, $M_n(D)$ be a matrix algebra over its center $K$. A classification of one-to-one $K$-linear mappings from $M_n(D)$ to $M_n(D)$ which preserves Diedonne determinant is obtained. Namely, $T(A)=P(A^s)Q$ for all matrices $A$ from $M_n(D)$ or $T(A)=P( (A^s)^t )Q$ for all matrices $A$ from $M_n(D)$, here $s$ denotes $K$-linear authomorphism of the skew-field $D$, and $t$ denotes transpose matrix. Computational algorithms for constracting matrices $P$ and $Q$ are proposed.