Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-29T10:32:41.610Z Has data issue: false hasContentIssue false

Condensation of homomorphism spaces

Published online by Cambridge University Press:  01 May 2012

Klaus Lux
Affiliation:
Department of Mathematics, The University of Arizona, Tucson, AZ 85721-0089, USA (email: [email protected])
Max Neunhöffer
Affiliation:
School of Mathematics and Statistics Mathematical Institute, University of St Andrews, North Haugh, St Andrews Fife KY16 9SS, United Kingdom (email: [email protected])
Felix Noeske
Affiliation:
Lehrstuhl D für Mathematik, RWTH Aachen University, 52056 Aachen, Germany (email: [email protected])

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We present an efficient algorithm for the condensation of homomorphism spaces. This provides an improvement over the known tensor condensation method which is essentially due to a better choice of bases. We explain the theory behind this approach and describe the implementation in detail. Finally, we give timings to compare with previous methods.

Type
Research Article
Copyright
Copyright © London Mathematical Society 2012

References

[1]Green, J. A., Polynomial representations of GL n, Lecture Notes in Mathematics 830 (Springer, Berlin, 1980).Google Scholar
[2]Holt, D. F. and Rees, S., ‘Testing modules for irreducibility’, J. Aust. Math. Soc. Ser. A 57 (1994) 116.CrossRefGoogle Scholar
[3]Lübeck, F. and Neunhöffer, M., ‘Direct condense 2’, 2000, http://www.math.rwth-aachen.de/∼DC/.Google Scholar
[4]Lux, K., Müller, J. and Ringe, M., ‘Peakword condensation and submodule lattices: an application of the Meat-Axe’, J. Symbolic Comput. 17 (1994) 529544.CrossRefGoogle Scholar
[5]Lux, K. and Wiegelmann, M., ‘Condensing tensor product modules’, The atlas of finite groups: ten years on (Birmingham, 1995), London Mathematical Society Lecture Note Series 249 (Cambridge University Press, Cambridge, 1998) 174190.Google Scholar
[6]Müller, J. and Rosenboom, J., ‘Condensation of induced representations and an application: the 2-modular decomposition numbers of Co 2’, Computational methods for representations of groups and algebras (Essen, 1997), Progress in Mathematics 173 (Birkhäuser, Basel, 1999) 309321.CrossRefGoogle Scholar
[7]Neunhöffer, M., ‘cvec: a GAP-package implementing compressed vectors and matrices’, 2006, http://www-groups.mcs.st-and.ac.uk/∼neunhoef/Computer/Software/GAP/cvec.html.Google Scholar
[8]Noeske, F., ‘Morita-Äquivalenzen in der algorithmischen Darstellungstheorie’, PhD Thesis, RWTH Aachen, 2005.Google Scholar
[9]Parker, R. A., ‘The computer calculation of modular characters (the meat-axe)’, Computational group theory (Durham, 1982) (Academic Press, London, 1984) 267274.Google Scholar
[10]Ringe, M., ‘The MeatAxe – computing with modular representations’, 2009, http://www.math.rwth-aachen.de/homes/MTX/.Google Scholar
[11]Ryba, A. J. E., ‘Condensation of symmetrized tensor powers’, J. Symbolic Comput. 32 (2001) 273289.CrossRefGoogle Scholar
[12]Thackray, J. G., ‘Modular representations of some finite groups’, PhD Thesis, University of Cambridge, 1981.Google Scholar
[13]Wilson, R., Thackray, J., Parker, R., Noeske, F., Müller, J., Lux, K., Lübeck, F., Jansen, C., Hiss, G. and Breuer, T., ‘The modular Atlas project’, 1998, http://www.math.rwth-aachen.de/∼MOC/.Google Scholar