arXiv subjects

A. Buium

Publications and source records attributed to A. Buium.

5 recordsLinked to original sources

arXiv2011

Differential overconvergence

We prove that some of the basic differential functions appearing in the (unramified) theory of arithmetic differential equations, especially some of the basic differential modular forms in that theory, arise from a "ramified situation". This property can be viewed as a special kind of overconvergence property. One can also go in the opposite direction by using differential functions that arise in a ramified situation to construct "new" (unramified) differential functions.

math.NT↗

arXiv2011

The ring of differential Fourier expansions

For a fixed prime we prove structure theorems for the kernel and the image of the map that attaches to any differential modular function its differential Fourier expansion. The image of this map, which is the ring of differential Fourier expansions, plays the role of ring of functions on a "differential Igusa curve". Our constructions are then used to perform an analytic continuation between isogeny covariant differential modular forms on the differential Igusa curves belonging to different primes.

math.NT↗

arXiv2011

Hecke operators on differential modular forms mod p

A description is given of all primitive differential series mod p of order 1 which are eigenvectors of all the Hecke operators and which are differential Fourier expansions of differential modular forms of arbitrary order and given weight; this set of differential series is shown to be in a natural one-to-one correspondence with the set of series mod p (of order 0) which are eigenvectors of all the Hecke operators and which are Fourier expansions of (classical) modular forms of appropriate weight.

math.NT↗

arXiv2008

Arithmetic differential operators on Z_p

We prove that a function f from Z_p to itself is analytic if and only if it can be represented as f(x)=F(x, dx, ..., d^r x) where dx=(x-x^p)/p is the Fermat quotient operator and F is a restricted power series with coefficients in Z_p.

math.NT↗

arXiv1994

Reduction of the Manin map modulo $p$

For an abelian variety $A$ over a function field $K$ of characteristic zero, Manin defined a remarkable additive map $A(K) \ra V$, where $V$ is a vector space over $K$. We define an analogue of this map in the case of function fields of characteristic $p$. We then prove that the reduction modulo $p$ of the Manin map in characteristic zero is the derivative of the Manin map in characteristic $p$ and that the kernel of the Manin map in characteristic $p$ is the group of points divisible by $p$.

alg-geom↗