A new class of non facet-to-facet random tessellations in three-dimensional space is introduced -the so-called column tessellations. The spatial construction is based on a stationary planar tessellation; each cell of the spatial tessellation is a prism whose base facet is congruent to a cell of the planar tessellation. Thus intensities and various mean values of the spatial tessellation can be calculated from suitably chosen parameters of the planar tessellation.Keywords: combinatorial topology, random tessellations, stochastic geometry.
THE CONTEXT FOR OUR NEW MODELRandom tessellations are classical structures considered by stochastic geometers. Two standard models are the Poisson hyperplane and Poisson Voronoi tessellations (Schneider and Weil, 2008;Chiu et al., 2013). In the planar case these tessellations are side-to-side, that is, each side of a polygonal tessellation cell coincides with a side of a neighbouring cell. In their three dimensional versions they are facetto-facet, meaning that each facet of a polyhedral cell coincides with a facet of a neighbouring cell.In recent years there has been a growing interest in tessellation models that do not have the stated coincidence for all sides or facets. A first systematic study of the effects when a three-dimensional tessellation is not facet-to-facet is given in Weiss and Cowan (2011). A recent study presented in Cowan and Thäle (2014) looks in depth at the planar case, building on results from the 1970s when non side-toside tessellations first attracted attention.Tessellations of that kind arise for example by cell division. Among these models, the iteration stable or STIT tessellation is of particular interest because of the number of analytically available results (Nagel and Weiss, 2005;Mecke et al., 2008;Thäle et al., 2012;Cowan, 2013;Thäle and Weiss, 2013, and the references therein). It serves as a reference model for geological crack and fissure structures (Mosser and Matthäi, 2014) and might have application in the process of biological cell division. The development of new model classes is important for further applications to random structures in materials science, geology and biology -and the current paper contributes to that aim.We consider a new class of non facet-to-facet spatial tessellations, whose construction is based on a stationary planar tessellation Y having convex polygonal cells. From each polygonal cell z of Y we form an infinite column perpendicular to the plane E in which Y lies. Any cross-section of the column parallel to E is congruent to z. To create a spatial tessellation, each infinite column is intersected by many such cross-sections, thereby dividing the column into cells. The spatial cells which arise are prisms and their polygonal base facets (located at the cross-sections) are translations (in the third dimension orthogonal to E ) of the cells of Y . The resulting three-dimensional tessellation Y is called a column tessellation. Column tessellations could be useful to describe crack structures in geology, as for e...