TY - GEN A1 - Tsarev, Sergey A1 - Wolf, Thomas T1 - Hyperdeterminants as integrable discrete systems N2 - We give the basic definitions and some theoretical results about hyperdeterminants, introduced by A.~Cayley in 1845. We prove integrability (understood as $4d$-consistency) of a nonlinear difference equation defined by the $2 \times 2 \times 2$ - hyperdeterminant. This result gives rise to the following hypothesis: the difference equations defined by hyperdeterminants of any size are integrable. We show that this hypothesis already fails in the case of the $2\times 2\times 2\times 2$ - hyperdeterminant. T3 - ZIB-Report - 09-17 KW - hyper determinants KW - integrable systems KW - discrete equations KW - large polynomial systems KW - computer algebra KW - Form KW - Reduce KW - Singular Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11292 SN - 1438-0064 ER - TY - GEN A1 - Wolf, Thomas T1 - Merging solutions of non-linear algebraic systems N2 - In solving large polynomial algebraic systems that are too big for standard Gröbner basis techniques one way to make progress is to introduce case distinctions. This divide and conquer technique can be beneficial if the algorithms and computer programs know how to take advantage of inequalities. A further hurdle is the form of the resulting general solutions which often have unnecessarily many branches. In this paper we discuss a procedure to merge solutions by dropping inequalities which are associated with them and, if necessary, by re-parametrizing solutions. In the appendix the usefulness of the procedure is demonstrated in the classification of quadratic Hamiltonians with a Lie-Poisson bracket $e(3)$. This application required the solution of algebraic systems with over 200 unknowns, 450 equations and between 5000 and 9000 terms. T3 - ZIB-Report - 10-13 KW - computer algebra KW - polynomial systems KW - Lie-Poisson brackets KW - quadratic Hamiltonians Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11769 SN - 1438-0064 ER - TY - GEN A1 - Wolf, Thomas A1 - Efimovskaya, Olya V. T1 - Classification of integrable quadratic Hamiltonians on e(3) N2 - Linear Poisson brackets on e(3) typical of rigid body dynamics are considered. All quadratic Hamiltonians of Kowalevski type having additional first integral of fourth degree are found. Quantum analogs of these Hamiltonians are listed. T3 - ZIB-Report - 10-18 KW - Linear Poisson brackets on e(3) KW - rigid body dynamics KW - Kowalevski type Hamiltonians KW - first integrals Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11807 SN - 1438-0064 ER -