Hostname: page-component-848d4c4894-r5zm4 Total loading time: 0 Render date: 2024-06-16T21:04:22.420Z Has data issue: false hasContentIssue false

Computing Borcherds products

Published online by Cambridge University Press:  01 August 2013

Dominic Gehre
Lehrstuhl A für Mathematik,RWTH Aachen University,Templergraben 55, D-52056 Aachen,Germany email
Judith Kreuzer
Lehrstuhl A für Mathematik,RWTH Aachen University,Templergraben 55, D-52056 Aachen,Germany email
Martin Raum
ETH Mathematics Department,Rämistraße 101, CH-8092, Zürich,Switzerland email


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 algorithm for computing Borcherds products, which has polynomial runtime. It deals efficiently with the bounds on Fourier expansion indices originating in Weyl chambers. Naive multiplication has exponential runtime due to inefficient handling of these bounds. An implementation of the new algorithm shows that it is also much faster in practice.

Research Article
© The Author(s) 2013 


Bruinier, J. and Ono, K., ‘Heegner divisors, $L$ -functions and harmonic weak Maass forms’, Ann. of Math. (2) 172 (2010) 21352181.CrossRefGoogle Scholar
Borcherds, R., ‘Automorphic forms on ${O}_{s+ 2, 2} (R)$ and infinite products’, Invent. Math. 120 (1995) 161213.CrossRefGoogle Scholar
Borcherds, R., ‘Automorphic forms with singularities on Grassmannians’, Invent. Math. 132 (1998) 491562.CrossRefGoogle Scholar
Borcherds, R., ‘The Gross–Kohnen–Zagier theorem in higher dimensions’, Duke Math. J. 97 (1999) 219233.CrossRefGoogle Scholar
Borcherds, R., ‘Correction to: The Gross–Kohnen–Zagier theorem in higher dimensions’, Duke Math. J. 105 (2000) 183184.CrossRefGoogle Scholar
Braun, H., ‘Hermitian modular functions’, Ann. of Math. (2) 50 (1949) 827855.CrossRefGoogle Scholar
Braun, H., ‘Hermitian modular functions. II’, Ann. of Math. (2) 51 (1950) 92104.CrossRefGoogle Scholar
Braun, H., ‘Hermitian modular functions III’, Ann. of Math. (2) 53 (1951) 143160.CrossRefGoogle Scholar
Bruinier, J., Borcherds products on O(2,l) and Chern classes of Heegner divisors, Lecture Notes in Mathematics 1780 (Springer, Berlin, 2002).CrossRefGoogle Scholar
Cléry, F. and Gritsenko, V., ‘Siegel modular forms of genus 2 with the simplest divisor’, Proc. Lond. Math. Soc. (3) 102 (2011) 10241052.CrossRefGoogle Scholar
Dern, T., ‘Hermitesche Modulformen zweiten Grades’, PhD Thesis, RWTH Aachen University, Germany, 2001.Google Scholar
Dabholkar, A. and Gaiotto, D., ‘Spectrum of CHL dyons from genus-two partition function’, J. High Energy Phys. 12 (2007) 087.CrossRefGoogle Scholar
Decker, W., Greuel, G., Pfister, G. and Schönemann, H., ‘Singular 3-1-1 — A computer algebra system for polynomial computations’, 2010, Scholar
Dern, T. and Krieg, A., ‘Graded rings of Hermitian modular forms of degree 2’, Manuscripta Math. 110 (2003) 251272.CrossRefGoogle Scholar
Dern, T. and Krieg, A., ‘The graded ring of Hermitian modular forms of degree 2 over $ \mathbb{Q} ( \sqrt{- 2} )$ ’, J. Number Theory 107 (2004) 241265.CrossRefGoogle Scholar
Dabholkar, A., Murthy, S. and Zagier, D., ‘Quantum black holes, wall crossing, and mock modular forms’, Preprint, 2012, arXiv:hep-th/1208.4074.Google Scholar
Freitag, E. and Hermann, C., ‘Some modular varieties of low dimension’, Adv. Math. 152 (2000) 203287.CrossRefGoogle Scholar
Gehre, D. and Krieg, A., ‘Quaternionic theta constants’, Arch. Math. 94 (2010) 5966.CrossRefGoogle Scholar
Gritsenko, V., ‘Arithmetical lifting and its applications’, Séminaire de théorie des nombres de Paris 1992–93 (ed. Sinnou, D.; Cambridge University Press, Cambridge, 1995) 103126.Google Scholar
Gritsenko, V. and Nikulin, V., ‘Automorphic forms and Lorentzian Kac–Moody algebras II’, Internat. J. Math. 9 (1998) 201275.CrossRefGoogle Scholar
Hart, W. B. et al. , ‘Fast library for number theory 1.5.2’, 2010, Scholar
Helgason, S., ‘Differential geometry’, Lie groups, and symmetric spaces, Pure and Applied Mathematics 80 (Academic Press Inc. [Harcourt Brace Jovanovich Publishers], New York, 1978).Google Scholar
Harvey, J. and Moore, G., ‘On the algebras of BPS states’, Comm. Math. Phys. 197 (1998) 489519.CrossRefGoogle Scholar
Heim, B. and Murase, A., ‘Borcherds lifts on ${\mathrm{Sp} }_{2} ( \mathbb{Z} )$ ’, Geometry and analysis of automorphic forms of several variables, Series on Number Theory and Its Applications 7 (World Scientific, Hackensack, NJ, 2012) 5676.Google Scholar
Jatkar, D. and Sen, A., ‘Dyon spectrum in CHL models’, J. High Energy Phys. 04 (2006) 018.CrossRefGoogle Scholar
Kontsevich, M., ‘Product formulas for modular forms on $\mathrm{O} (2, n)$ (after R. Borcherds)’, Astérisque (1997) no. 245, Exp. No. 821, 3, 41–56, Séminaire Bourbaki, Vol. 1996/97.Google Scholar
Krieg, A., ‘The graded ring of quaternionic modular forms of degree 2’, Math. Z. 251 (2005) 929942.CrossRefGoogle Scholar
Gopala Krishna, K., ‘BKM Lie superalgebra for the ${Z}_{5} $ -orbifolded CHL string’, J. High Energy Phys. 02 (2012) 089.CrossRefGoogle Scholar
Mayer, S., ‘Calculation of Hilbert Borcherds products’, Experiment. Math. 19 (2010) 243256.CrossRefGoogle Scholar
O’Meara, O., ‘Introduction to quadratic forms’, Classics in Mathematics (Springer, Berlin, 2000) . Reprint of the 1973 edition.Google Scholar
Raum, M., ‘How to implement a modular form’, J. Symb. Comp. 46 (2011) 13361354.CrossRefGoogle Scholar
Raum, M., ‘Computing Jacobi forms and linear equivalences of special divisors’, Preprint, 2012, arXiv: 1212.1834.Google Scholar
Raum, M., ‘Homepage’, 2012, Scholar
Raum, M., ‘PSage repository on GitHub’, 2012, Scholar
Stein, W. et al. , ‘Purple Sage’, 2011, Scholar
Stein, W. et al. , ‘Sage Mathematics Software (Version 5.0.1)’, The Sage Development Team, 2012, Scholar
Scheithauer, N., ‘Generalized Kac–Moody algebras, automorphic forms and Conway’s group. I’, Adv. Math. 183 (2004) 240270.CrossRefGoogle Scholar
Scheithauer, N., ‘Generalized Kac–Moody algebras, automorphic forms and Conway’s group. II’, J. reine angew. Math. 625 (2008) 125154.Google Scholar
Siegel, C., ‘Indefinite quadratische Formen und Funktionentheorie. I’, Math. Ann. 124 (1951) 1754.CrossRefGoogle Scholar
Skoruppa, N., ‘Jacobi forms of critical weight and Weil representations’, Modular Forms on Schiermonnikoog (eds Edixhoven, B., Geer, G. V. D. and Moonen, B.; Cambridge University Press, Cambridge, 2008).Google Scholar
Torvald, L. et al. , ‘git version control system’,, 2012.Google Scholar