Abstract: The aim of this paper is to give a survey on analytic representations of central and orthographic projections from R^4 to R^3 or R^2. There are discussed various aspects of these projections, whereby some special relations were revealed, e.g., the fact that homogeneous coordinates or barycentric coordinates in R^3 can be obtained by applying particular projections on a point with given cartesian coordinates in R^4. We would also like to demonstrate that by projecting curves or 2-surfaces of R^4 interesting shapes in R^3 and R^2 can be obtained.
Keywords: geometry in 4D, projections, quaternions
Classification (MSC2000): 51N20; 51N05
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