Khayyam Journal of Mathematics

Khayyam Journal of Mathematics

The Multiplicative Tensor Product of n-fold Matrix Factorization of Polynomials

Document Type : Original Article

Author
{Department of Mathematics‎, ‎HTTC‎, ‎ University of Bamenda‎, ‎Bambili‎, ‎Cameroon.
Abstract
The motivation behind this work is the generalization of the construction of the multiplicative tensor product of matrix factorizations. In fact, in this paper, we first construct for each $n\geq 2$, three bifunctorial operations $\widetilde{\otimes}_{n}$, $\overline{\otimes}_{n}$ and $\widetilde{\otimes}_{n}'$ which are such that if $X$ (respectively $Y$) is an $n-$fold matrix factorization of $f\in K[x_{1},x_{2},\cdots, x_{r}]$ (respectively $g\in K[y_{1},y_{2},\cdots, y_{s}]$), then both $X\widetilde{\otimes}_{n} Y$ and $X\widetilde{\otimes}_{n}' Y$ are $n-$fold matrix factorizations of $fg\in K[x_{1},x_{2},\cdots, x_{r},y_{1},y_{2},\cdots, y_{s}]$. When $n$ is even, $X \widetilde{\otimes}_{n}' Y$ is an $n-$fold matrix factorization of $fg\in K[x_{1},x_{2},\cdots, x_{r},y_{1},y_{2},\cdots, y_{s}]$. We call $\widetilde{\otimes}_{n}$ the multiplicative tensor product of $n-$fold matrix factorizations, $\overline{\otimes}_{n}$ its refined version and $\widetilde{\otimes}_{n}'$ its variant.
Next, the associativity of these operations is proven. Moreover, we show that for each $n\geq 2$, $\widetilde{\otimes}_{n}$ can readily be used to construct a \textit{semi-unital semi-monoidal category}.
Finally, we briefly compare the operations $\widetilde{\otimes}_{n}$, $\overline{\otimes}_{n}$ and $\widetilde{\otimes}_{n}'$.
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