Beiträge zur Algebra und Geometrie Contributions to Algebra and Geometry Vol. 46, No. 2, pp. 587608 (2005) 

General projections in spaces of pencilsKrzysztof Pra\.zmowski and Mariusz \.ZynelInstitute of Mathematics, University of Bia{\l}ystok, Akademicka 2, 15267 Bia{\l}ystok, Poland; email: krzypraz@math.uwb.edu.pl email:mariusz@math.uwb.edu.plAbstract: The notion of the central projection in spaces of pencils is generalized and new concepts of projections are introduced. The category of projectivities with segment subspaces as objects arises. These general projectivities are collineations given by linear maps. Properties of pencils of segment subspaces and projections between segments are investigated. Classical projections of lines onto pencils of hyperplanes are considered in terms of spaces of pencils as projections of lines onto pencils of segment subspaces. Full text of the article:
Electronic version published on: 18 Oct 2005. This page was last modified: 29 Dec 2008.
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