563 research outputs found
Upper bound on the number of systems of Hecke eigenvalues for Siegel modular forms (mod p)
We derive an explicit upper bound for the number of systems of Hecke
eigenvalues coming from Siegel modular forms (mod p) of dimension g and level N
relatively prime to p. In the special case of elliptic modular forms (g=1), our
result agrees with recent work of G. Herrick.Comment: 4 pages, amsart class; included reference to current work of G.
Herrick; fixed a small error in the estimate of Corollary
Hecke eigenvalues of Siegel modular forms (mod p) and of algebraic modular forms
In a letter to Tate (published in Israel J. Math. in 1996), J.-P. Serre
proves that the systems of Hecke eigenvalues given by modular forms (mod p) are
the same as the ones given by locally constant functions on an adelic double
coset space constructed from the endomorphism algebra of a supersingular
elliptic curve. We generalize this result to Siegel modular forms, proving that
the systems of Hecke eigenvalues given by Siegel modular forms (mod p) are the
same as the ones given by algebraic modular forms (mod p) on a quaternionic
unitary group, as defined by Gross in Israel J. Math. in 1999. The
correspondence is obtained by restricting to the superspecial locus of the
moduli space of abelian varieties.Comment: 28 pages; submitted to the Journal of Number Theory. Based on chapter
3 of math.NT/0306224, reworked and corrected. Comments are welcom
Distinguishing eigenforms modulo a prime ideal
Consider the Fourier expansions of two elements of a given space of modular
forms. How many leading coefficients must agree in order to guarantee that the
two expansions are the same? Sturm gave an upper bound for modular forms of a
given weight and level. This was adapted by Ram Murty, Kohnen and Ghitza to the
case of two eigenforms of the same level but having potentially different
weights. We consider their expansions modulo a prime ideal, presenting a new
bound. In the process of analysing this bound, we generalise a result of Bach
and Sorenson, who provide a practical upper bound for the least prime in an
arithmetic progression.Comment: 13 page
Distinguishing newforms
Let be the number of initial Fourier coefficients necessary to
distinguish newforms of level and even weight . We produce extensive
data to support our conjecture that if is a fixed squarefree positive
integer and is large then is the least prime that does not
divide .Comment: 15 pages, 8 table
The 2008 election: A preregistered replication analysis
We present an increasingly stringent set of replications of Ghitza & Gelman
(2013), a multilevel regression and poststratification analysis of polls from
the 2008 U.S. presidential election campaign, focusing on a set of plots
showing the estimated Republican vote share for whites and for all voters, as a
function of income level in each of the states.
We start with a nearly-exact duplication that uses the posted code and
changes only the model-fitting algorithm; we then replicate using
already-analyzed data from 2004; and finally we set up preregistered
replications using two surveys from 2008 that we had not previously looked at.
We have already learned from our preliminary, non-preregistered replication,
which has revealed a potential problem with the published analysis of Ghitza &
Gelman (2013); it appears that our model may not sufficiently account for
nonsampling error, and that some of the patterns presented in that earlier
paper may simply reflect noise.
In addition to the substantive interest in validating earlier findings about
demographics, geography, and voting, the present project serves as a
demonstration of preregistration in a setting where the subject matter is
historical (and thus the replication data exist before the preregistration plan
is written) and where the analysis is exploratory (and thus a replication
cannot be simply deemed successful or unsuccessful based on the statistical
significance of some particular comparison).Comment: This article is a review and preregistration plan. It will be
published, along with a new Section 5 describing the results of the
preregistered analysis, in Statistics and Public Polic
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