17 research outputs found
Tables of subspace codes
One of the main problems of subspace coding asks for the maximum possible
cardinality of a subspace code with minimum distance at least over
, where the dimensions of the codewords, which are vector
spaces, are contained in . In the special case of
one speaks of constant dimension codes. Since this (still) emerging
field is very prosperous on the one hand side and there are a lot of
connections to classical objects from Galois geometry it is a bit difficult to
keep or to obtain an overview about the current state of knowledge. To this end
we have implemented an on-line database of the (at least to us) known results
at \url{subspacecodes.uni-bayreuth.de}. The aim of this recurrently updated
technical report is to provide a user guide how this technical tool can be used
in research projects and to describe the so far implemented theoretic and
algorithmic knowledge.Comment: 44 pages, 6 tables, 7 screenshot
Combining subspace codes
In the context of constant--dimension subspace codes, an important problem is
to determine the largest possible size of codes whose codewords
are -subspaces of with minimum subspace distance . Here
in order to obtain improved constructions, we investigate several approaches to
combine subspace codes. This allow us to present improvements on the lower
bounds for constant--dimension subspace codes for many parameters, including
, , and .Comment: 17 pages; construction for A_(10,4;5) was flawe