On the Sparseness of Certain MRD Codes
arXiv:1906.11691
Abstract
We determine the proportion of -MRD codes over within the space of all -dimensional -rank-metric codes over the same field. This shows that for these parameters MRD codes are sparse in the sense that the proportion tends to as . This is so far the only parameter case for which MRD codes are known to be sparse. The computation is accomplished by reducing the space of all such rank-metric codes to a space of specific bases and subsequently making use of a result by Menichetti (1973) on 3-dimensional semifields.