SPONTANEOUS GENERATION OF MODULAR INVARIANTS

Authors
Citation
H. Cohn et J. Mckay, SPONTANEOUS GENERATION OF MODULAR INVARIANTS, Mathematics of computation, 65(215), 1996, pp. 1295-1309
Citations number
14
Categorie Soggetti
Mathematics,Mathematics
Journal title
ISSN journal
00255718
Volume
65
Issue
215
Year of publication
1996
Pages
1295 - 1309
Database
ISI
SICI code
0025-5718(1996)65:215<1295:SGOMI>2.0.ZU;2-G
Abstract
It is possible to compute j(tau) and its modular equations with no per ception of its related classical group structure except at infinity. W e start by taking, for p prime, an unknown ''p-Newtonian'' polynomial equation g(u, v) = 0 with arbitrary coefficients (based only on Newton 's polygon requirements at infinity for u = j(tau) and v = j(pr)). We then ask which choice of coefficients of g(u, v) leads to some consist ent Laurent series solution u = u(q) approximate to 1/q, v = u(q(p)) ( where q = exp 2 pi i tau). It is conjectured that if the same Lament s eries u(q) works for p-Newtonian polynomials of two or more primes p, then there is only a bounded number of choices for the Laurent series (to within an additive constant). These choices are essentially from t he set of ''replicable functions,'' which include more classical modul ar invariants, particularly u = j(tau). A demonstration for orders p = 2 and 3 is done by computation. More remarkably, if the same series u (q) works for the p-Newtonian polygons of 15 special ''Fricke-Monster' ' values of p, then (u=)j(tau) is (essentially) determined uniquely. C omputationally, this process stands alone, and, in a sense, modular in variants arise ''spontaneously.''