activity
20112026
most citedFiniteness theorems for K3 surfaces and abelian varieties of CM type

26 citations · 103 across the 16 of their papers we have counts for

collaborators

18 papers

math.NT2026

Explicit height bounds for G-functions and unlikely intersections with lines in tori

Martin Orr

This paper computes explicit constants in Bombieri and André's height bound for points at which there are unexpected "global" polymomial relations between values of G-functions. It…

math.NT2025

Some new cases of Zilber-Pink in

Christopher Daw, Martin Orr, Georgios Papas

We prove the Zilber-Pink conjecture for curves in that intersect a modular curve in the boundary. We also give an unconditional result for unlikely intersection points hav…

math.AG2023

Extension of relative rigid homomorphisms from the formal multiplicative group

Martin Orr

A theorem of Lütkebohmert states that a rigid group homomorphism from the formal multiplicative group to a smooth commutative rigid group , with relatively compact image, can be…

math.NT2023

The large Galois orbits conjecture under multiplicative degeneration

Christopher Daw, Martin Orr

We establish the PEL type large Galois orbits conjecture for Hodge generic curves in possessing multiplicative degeneration. Combined with our earlier works, this c…

math.NT2022★ 1 cited

Zilber-Pink in a product of modular curves assuming multiplicative degeneration

Christopher Daw, Martin Orr

We prove the Zilber--Pink conjecture for curves in whose Zariski closure in passes through the point , going beyond the asymme…

math.NT2021★ 2 cited

Lattices with skew-Hermitian forms over division algebras and unlikely intersections

Christopher Daw, Martin Orr

This paper has two objectives. First, we study lattices with skew-Hermitian forms over division algebras with positive involutions. For division algebras of Albert types I and II,…

math.AG2020

Invariant Brauer group of an abelian variety

Martin Orr, Alexei N. Skorobogatov, Domenico Valloni +1

We study a new object that can be attached to an abelian variety or a complex torus: the invariant Brauer group, as recently defined by Yang Cao. Over the field of complex numbers…

math.NT2019★ 10 cited

Quantitative reduction theory and unlikely intersections

Christopher Daw, Martin Orr

We prove quantitative versions of Borel and Harish-Chandra's theorems on reduction theory for arithmetic groups. Firstly, we obtain polynomial bounds on the lengths of reduced inte…

math.NT2019★ 2 cited

Unlikely intersections with CM curves in

Christopher Daw, Martin Orr

The Zilber-Pink conjecture predicts that an algebraic curve in has only finitely many intersections with the special curves, unless it is contained in a proper spec…

math.AG2018★ 1 cited

Galois conjugates of special points and special subvarieties in Shimura varieties

Martin Orr

Let be a Shimura variety with reflex field . We prove that the action of on maps special points to special points and speci…

math.NT2018★ 6 cited

On uniformity conjectures for abelian varieties and K3 surfaces

Martin Orr, Alexei N. Skorobogatov, Yuri G. Zarhin

We discuss logical links among uniformity conjectures concerning K3 surfaces and abelian varieties of bounded dimension defined over number fields of bounded degree. The conjecture…

math.NT2017★ 3 cited

Unlikely intersections with Hecke translates of a special subvariety

Martin Orr

We prove some cases of the Zilber-Pink conjecture on unlikely intersections in Shimura varieties. Firstly, we prove that the Zilber-Pink conjecture holds for intersections between…

math.AG2017★ 26 cited

Finiteness theorems for K3 surfaces and abelian varieties of CM type

Martin Orr, Alexei N. Skorobogatov

We study abelian varieties and K3 surfaces with complex multiplication defined over number fields of fixed degree. We show that these varieties fall into finitely many isomorphism…

math.NT2016★ 20 cited

Height bounds and the Siegel property

Martin Orr

Let be a reductive group defined over and let be a Siegel set in . The Siegel property tells us that there are only…

math.NT2015★ 5 cited

On compatibility between isogenies and polarisations of abelian varieties

Martin Orr

We discuss the notion of polarised isogenies of abelian varieties, that is, isogenies which are compatible with given principal polarisations. This is motivated by problems of unli…

math.NT2015★ 6 cited

Heights of pre-special points of Shimura varieties

Christopher Daw, Martin Orr

Let s be a special point on a Shimura variety, and x a pre-image of s in a fixed fundamental set of the associated Hermitian symmetric domain. We prove that the height of x is poly…

math.AG2012★ 21 cited

Families of abelian varieties with many isogenous fibres

Martin Orr

Let Z be a subvariety of the moduli space of principally polarised abelian varieties of dimension g over the complex numbers. Suppose that Z contains a Zariski dense set of points…

math.AG2011

Lower bounds for ranks of Mumford-Tate groups

Martin Orr

Let A be a complex abelian variety and G its Mumford--Tate group. Supposing that the simple abelian subvarieties of A are pairwise non-isogenous, we find a lower bound for the rank…