Ehemalige Mitarbeiter

Prof. Dr. Martin Lotz

Kontakt
Mathematics Institute
Zeeman Building
University of Warwick
Coventry CV4 7AL
United Kingdom

Persönliche Homepage
http://homepages.warwick.ac.uk/staff/Martin.Lotz/

The complexity of computing the Hilbert polynomial of smooth equidimensional complex projective varieties
Zitatschlüssel	BL-The-Complexity-Of-Computing-The-Hilbert-Polynomial-Of-Smooth-Equidimensional-Complex-Projective-Varieties
Autor	Peter Bürgisser and Martin Lotz
Seiten	51-86
Jahr	2007
Journal	Foundations of Computational Mathematics
Jahrgang	7
Nummer	1
Zusammenfassung	We continue the study of counting complexity begun in [Buergisser, Cucker, Lotz 04] by proving upper and lower bounds on the complexity of computing the Hilbert polynomial of a homogeneous ideal. We show that the problem of computing the Hilbert polynomial of a smooth equidimensional complex projective variety can be reduced in polynomial time to the problem of counting the number of complex common zeros of a finite set of multivariate polynomials. Moreover, we prove that the more general problem of computing the Hilbert polynomial of a homogeneous ideal is polynomial space hard. This implies polynomial space lower bounds for both the problems of computing the rank and the Euler characteristic of cohomology groups of coherent sheaves on projective space, improving the #P-lower bound in [Bach 99].