Coordinate-wise Powers of Algebraic Varieties
Papri Dey, Paul Görlach, and Nidhi Kaihnsa
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Submission date: 10. Jul. 2018
Link to arXiv: See the arXiv entry of this preprint.
We introduce and study coordinate-wise powers of subvarieties of ℙn, i.e. varieties arising from raising all points in a given subvariety of ℙn to the r-th power, coordinate by coordinate. This corresponds to studying the image of a subvariety of ℙn under the quotient of ℙn by the action of the ﬁnite group ℤrn+1. We determine the degree of coordinate-wise powers and study their deﬁning equations, particularly for hypersurfaces and linear spaces. Applying these results, we compute the degree of the variety of orthostochastic matrices and determine iterated dual and reciprocal varieties of power sum hypersurfaces. We also establish a link between coordinate-wise squares of linear spaces and the study of real symmetric matrices with a degenerate eigenspectrum.