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Faculty Publication: Assistant Professor of Mathematics John Bergdall

July 15, 2019

SLOPES OF MODULAR FORMS AND THE GHOST CONJECTURE, II

Authors: Bergdall, John; Pollack, Robert

Source: TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY, 372 (1):357-388; 10.1090/tran/7549 JUL 1 2019 

Publication Type: Journal Article

Abstract: In a previous article we constructed an entire power series over p-adic weight space (the ghost series) and conjectured, in the Gamma(0)(N)-regular case, that this series encodes the slopes of overconvergent modular forms of any p-adic weight. In this paper, we construct abstract ghost series which can be associated to various natural subspaces of overconvergent modular forms. This abstraction allows us to generalize our conjecture to, for example, the case of slopes of overconvergent modular forms with a fixed residual representation that is locally reducible at p. Ample numerical evidence is given for this new conjecture. Further, we prove that the slopes computed by any abstract ghost series satisfy a distributional result at classical weights (consistent with conjectures of Gouvea) while the slopes form unions of arithmetic progressions at all weights not in Z(p).

Department of Mathematics