In this paper we investigate linear error correcting codes and projective caps related to the Grassmann embedding ε k of an orthogonal Grassmannian ∆k. In particular, we determine some of the parameters of the codes arising from the projective system determined by ε k (∆k). We also study special sets of points of ∆k which are met by any line of ∆k in at most 2 points and we show that their imag...

We give an elementary explicit construction of cell decomposition of the mod-uli space of projective structures on a two dimensional surface, analogous to the decomposition of Penner/Strebel for moduli space of complex structures. The relations between projective structures and P GL(2, C) flat connections are also described.

Quite recently, GOODMAN, POLLACK, WENGER and ZAMFIRESCU [7], [8] have proven two conjectures by GRÜNBAUM right, showing that any arrangement of pseudolines in the plane can be embedded into a flat projective plane and that there exists a universal topological projective plane in which every arrangement of pseudolines is stretchable. By FOLKMAN and LAWRENCE's theorem [6], this plane contains eve...

in this paper we have generalized the concepts of ,q-fuzzy ideals, ,q-fuzzy quasi-ideals and,q-fuzzy bi-ideals by introducing the concepts of   k ,q -fuzzy ideals,   k ,q -fuzzy quasiideals and   k ,q -fuzzy bi-ideals in ternary semigroups and several related properties are investigated. different characterizations of regular and weakly regular ternary semigroups b...