Symmetric planes

Determination of symmetric and asymmetric division planes in plant cells.

The cellular organization of plant tissues is determined by patterns of cell division and growth coupled with cellular differentiation. Cells proliferate mainly via symmetric division, whereas asymmetric divisions are associated with initiation of new developmental patterns and cell types. Division planes in both symmetrically and asymmetrically dividing cells are established through the action...

Minimal symmetric differences of lines in projective planes

Let q be an odd prime power and let f(r) be the minimum size of the symmetric difference of r lines in the Desarguesian projective plane PG(2, q). We prove some results about the function f(r), in particular showing that there exists a constant C > 0 such that f(r) = O(q) for Cq3/2 < r < q2 − Cq3/2.

Realization of Hermitian Symmetric Spaces as Generalized Half-planes

flambement des structures planes

l&apos;utilisation de nouvaux materiaux aux caracteristiques mecaniques elevtes et le perfectionement continu des methodes de calcu1,incitent les constructeur a edifier des structures de plus cn plus elancees , de ce fait le probleme du flambement prend une importance sans cesse accrue. la prtsente etude se rapporte a etablir les equations intrinseques d&apos;une poutre droite a section constan...

Omittable Planes

In analogy to omittable lines in the plane, we initiate the study of omittable planes in 3-space. Given a collection of n planes in real projective 3-space, a plane Π is said to be omittable if Π is free of ordinary lines of intersection – in other words, if all the lines of intersection of Π with other planes from the collection come at the intersection of three or more planes. We provide two ...