The Countability of a Tiling Family and the Periodicity of a Tiling.
The local theorem for monotypic tilings.
The lonely vertex problem.
The optimal ball and horoball packings of the Coxeter tilings in the hyperbolic 3-space.
The optimal ball and horoball packings to the Coxeter honeycombs in the hyperbolic -space.
The possibility of extending factorization results to infinite Abelian groups.
The projective interpretation of the eight 3-dimensional homogeneous geometries.
The size of an annihilator in a factorization.
Tiling with L's and squares.
Tilings in topological spaces.
Tropical convexity.