Planar coincidences for N-fold symmetry

We develop the methods used by Rudnev and Wheeler to prove an incidence theorem between arbitrary sets of M\"{o}bius transformations and point sets in $\mathbb F_p^2$. We also note some asymmetric incidence results, and give applications of these results to various problems in additive combinatorics and discrete geometry.

We investigate an algebraic problem related to the determination of the fundamental group of a class of spaces of configurations on surfaces. The configuration spaces are spaces of points grouped into colors. Whether two points are allowed to collide is determined by a graph, whose vertices are the colors. In an earlier paper, the fundamental group of such graphs was described as solutions to linear Diophantine equations. In this paper, the problem of describing the set of ...

In this paper, we study the isomorphism problem for linear representations. A linear representation Tn*(K) of a point set K is a point-line geometry, embedded in a projective space PG(n+1,q), where K is contained in a hyperplane. We put constraints on K which ensure that every automorphism of Tn*(K) is induced by a collineation of the ambient projective space. This allows us to show that, under certain conditions, two linear representations Tn*(K) and Tn*(K') are isomorphic i...

In this work, we reconsider the study of 2D materials involving double lattice structures associated with periodic polygons. In tessellated periodic representation, it appears two periodic polygons of $k$ sides of unequal side lengths at certain angles fixed by the underlying discrete symmetries. In this way, 2D materials could be engineered by using two superstructures on the same atomic sheet generated by two length parameters $a_{1}$ and $a_{2}$ and rotated by the angle $\...

The content of this preprint together with additional material appears now in 0706.2154.

Given $A\subset\mathbb Z_n^2$, the purpose of this article is to investigate when is the difference set $\Delta A$ disjoint with the zero set of the Fourier transform of $A$. In the study of tiles in $\mathbb Z_n^2$, the author observed an interesting phenomenon that if $(A,B)$ is a tiling pair with $|A|=|B|$, then sometimes $(A,B)$ is also a spectral pair and vice versa. Moreover, in such cases actually one of the components would have universality (i.e., it is the universal...

This paper shows that a multiple translative tile in the plane must be a multiple lattice tile.

We describe a computer algorithm that searches for substitution rules on a set of triangles, the angles of which are all integer multiples of {\pi}/n. We find new substitution rules admitting 7-fold rotational symmetry at many different inflation factors.

We characterize conjugacy classes of isometries of odd prime order in unimodular Z-lattices. This is applied to give a complete classification of odd prime order non-symplectic automorphisms of irreducible holomorphic symplectic manifolds up to deformation and birational conjugacy.

In this paper we prove that if $S$ is any finite configuration of points in $\mathbb{Z}^2$, then any finite coloring of $\mathbb{E}^2$ must contain uncountably many monochromatic subsets homothetic to $S$. We extend a result of Brown, Dunfield, and Perry on 2-colorings of $\mathbb{E}^2$ to any finite coloring of $\mathbb{E}^2$.