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The generalized projection-tensor geometry introduced in an earlier paper is extended. A compact notation for families of projected objects is introduced and used to summarize the results of the previous paper and obtain fully projected…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Robert H. Gowdy

We characterize 1-complemented subspaces of finite codimension in strictly monotone one-$p$-convex, $2<p<\infty,$ sequence spaces. Next we describe, up to isometric isomorphism, all possible types of 1-unconditional structures in sequence…

Functional Analysis · Mathematics 2016-09-06 Beata Randrianantoanina

In this article we give a classification of the binary, simple, $\omega$-categorical structures with SU-rank 1 and trivial pregeometry. This is done both by showing that they satisfy certain extension properties, but also by noting that…

Logic · Mathematics 2017-04-11 Ove Ahlman

Cliquewidth is a dense analogue of treewidth. It can be deduced from recent results by Hickingbotham [arXiv:2501.10840] and Nguyen, Scott, and Seymour [arXiv:2501.09839] that graphs of bounded cliquewidth are quasi-isometric to graphs of…

Combinatorics · Mathematics 2025-05-26 Marc Distel

We prove a restricted projection theorem for an n-2 dimensional family of projections from $\mathbb R^n$ to $\mathbb R$. The family we consider arises naturally in the context of the adjoint representation of the maximal unipotent subgroup…

Classical Analysis and ODEs · Mathematics 2023-05-23 K. W. Ohm

The notion of chain groups of homeomorphisms of the interval was introduced by Kim, Koberda and Lodha as a generalization of Thompson's group $F$. In this paper, we study an $S^1$-version of chain groups: ring groups. We study the…

Group Theory · Mathematics 2025-09-12 Motoko Kato

Determining whether two graphs are isomorphic is an important and difficult problem in graph theory. One way to make progress towards this problem is by finding and studying graph invariants that distinguish large classes of graphs. Stanley…

Combinatorics · Mathematics 2020-10-22 Jeremy Zhou

In this article, we study quasimaps to moduli spaces of sheaves on a $K3$ surface $S$. We construct a surjective cosection of the obstruction theory of moduli spaces of quasimaps. We then establish reduced wall-crossing formulas which…

Algebraic Geometry · Mathematics 2025-03-20 Denis Nesterov

By a [$K$-]approximate subring of a ring we mean an additively symmetric subset $X$ such that $X \cdot X \cup (X + X)$ is covered by finitely many [resp.\ $K$] additive translates of $X$. We prove a structure theorem for finite approximate…

Rings and Algebras · Mathematics 2026-04-07 Krzysztof Krupiński , Simon Machado

In this paper, we characterise graphs that are quasi-isometric to graphs with bounded treewidth. Specifically, we prove that a graph is quasi-isometric to a graph with bounded treewidth if and only if it has a tree-decomposition where each…

Combinatorics · Mathematics 2025-08-21 Robert Hickingbotham

We develop in detail the theory of c-projective geometry, a natural analogue of projective differential geometry adapted to complex manifolds. We realise it as a type of parabolic geometry and describe the associated Cartan or tractor…

Differential Geometry · Mathematics 2021-06-08 David M. J. Calderbank , Michael G. Eastwood , Vladimir S. Matveev , Katharina Neusser

We develop the basic theory of projective modules and splitting in the more general setting of systems. Systems provide a common language for most tropical algebraic approaches including supertropical algebra, hyperrings (specifically…

Commutative Algebra · Mathematics 2019-04-16 Jaiung Jun , Kalina Mincheva , Louis Rowen

We present a sheaf-theoretic construction of shape space -- the space of all shapes. We do this by describing a homotopy sheaf on the poset category of constructible sets, where each set is mapped to its Persistent Homology Transform (PHT).…

Algebraic Topology · Mathematics 2023-06-26 Shreya Arya , Justin Curry , Sayan Mukherjee

We show that the fundamental groups of any two closed irreducible non-geometric graph-manifolds are quasi-isometric. This answers a question of Kapovich and Leeb. We also classify the quasi-isometry types of fundamental groups of…

Geometric Topology · Mathematics 2010-04-13 Jason A. Behrstock , Walter D. Neumann

We prove that the inclusion from oriented graph complex into graph complex with at least one source is a quasi-isomorphism, showing that homology of the "sourced" graph complex is also equal to the homology of standard Kontsevich's graph…

Quantum Algebra · Mathematics 2018-02-14 Marko Živković

We give some new explicit examples of putatively optimal projective spherical designs. i.e., ones for which there is numerical evidence that they are of minimal size. These form continuous families, and so have little apparent symmetry in…

Combinatorics · Mathematics 2025-03-20 Alex Elzenaar , Shayne Waldron

Labourie and the author independently showed that a convex real projective structure on an oriented surface of genus at least 2 is equivalent to a conformal structure plus a holomorphic cubic differential U. We analyze the behavior of the…

Differential Geometry · Mathematics 2007-05-23 John C. Loftin

Given a polarized abelian scheme with action by a ring, and a projective finitely presented module over that ring, Serre's tensor construction produces a new abelian scheme. We show that to equip these abelian schemes with polarizations…

Number Theory · Mathematics 2017-10-17 Zavosh Amir-Khosravi

We generalize Hrushovski's Group Configuration Theorem to quasiminimal classes. As an application, we present Zariski-like structures, a generalization of Zariski geometries, and show that a group can be found there if the pregeometry…

Logic · Mathematics 2017-02-09 Tapani Hyttinen , Kaisa Kangas

Given a graded monoid A with 1, one can construct a projective monoid scheme MProj(A) analogous to Proj(R) of a graded ring R. This paper is concerned with the study of quasicoherent sheaves (of pointed sets) on MProj(A), and we prove…

Algebraic Geometry · Mathematics 2016-02-18 Oliver Lorscheid , Matt Szczesny