Matthias Koch

activity

20062015

most cited

2

-arcs of maximal size in the affine and the projective Hjelmslev plane over

Z_{25}

6 citations · 10 across the 3 of their papers we have counts for

collaborators

3 papers

math.CO2015★ 3 cited

New complete 2-arcs in the uniform projective Hjelmslev planes over chain rings of order 25

Michael Kiermaier, Matthias Koch

In this paper a 2-arc of size 21 in the projective Hjelmslev plane PHG(2,\Z_25) and a 2-arc of size 22 in PHG(2,\F_5[X]/(X^2)) are given. Both arcs are bigger than the 2-arcs previ…

math.CO2014★ 6 cited

$2$ -arcs of maximal size in the affine and the projective Hjelmslev plane over $Z_{25}$

Michael Kiermaier, Matthias Koch, Sascha Kurz

It is shown that the maximal size of a $2$ -arc in the projective Hjelmslev plane over $Z_{25}$ is $21$ , and the $(21, 2)$ -arc is unique up to isomorphism. Furthermore, all…

math.CO2006★ 1 cited

Enumeration of generalized polyominoes

Matthias Koch, Sascha Kurz

As a generalization of polyominoes we consider edge-to-edge connected nonoverlapping unions of regular $k$ -gons. For $n \leq 4$ we determine formulas for the number $a_{k} (n)$ of gener…

New complete 2-arcs in the uniform projective Hjelmslev planes over chain rings of order 25

2-arcs of maximal size in the affine and the projective Hjelmslev plane over Z25​

Enumeration of generalized polyominoes

$2$ -arcs of maximal size in the affine and the projective Hjelmslev plane over $Z_{25}$