Results 31 to 40 of about 3,689 (160)

Singularities of eight- and nine-particle amplitudes from cluster algebras and tropical geometry [PDF]

Journal of High Energy Physics, 2021
Abstract We further exploit the relation between tropical Grassmannians and Gr(4, n) cluster algebras in order to make and refine predictions for the singularities of scattering amplitudes in planar $$ \mathcal{N} $$ N = 4 super Yang-Mills theory at higher multiplicity n ≥ 8.
Henke, N., Papathanasiou, G.
openaire   +6 more sources

Chern-Simons: Fano and Calabi-Yau

Advances in High Energy Physics, 2011
We present the complete classification of smooth toric Fano threefolds, known to the algebraic geometry literature, and perform some preliminary analyses in the context of brane tilings and Chern-Simons theory on M2-branes probing Calabi-Yau fourfold ...
Amihay Hanany, Yang-Hui He
doaj   +1 more source

Local Euler characteristics of $A_n$-singularities and their application to hyperbolicity [PDF]

Épijournal de Géométrie Algébrique
Wahl's local Euler characteristic measures the local contributions of a singularity to the usual Euler characteristic of a sheaf. Using tools from toric geometry, we study the local Euler characteristic of sheaves of symmetric differentials for isolated ...
Nils Bruin, Nathan Ilten, Zhe Xu
doaj   +1 more source

Finitely curved orbits of complex polynomial vector fields

Anais da Academia Brasileira de Ciências, 2007
This note is about the geometry of holomorphic foliations. Let X be a polynomial vector field with isolated singularities on C². We announce some results regarding two problems: 1.
Albetã C. Mafra
doaj   +1 more source

Murphy’s law in algebraic geometry: Badly-behaved deformation spaces [PDF]

, 2004
We consider the question: “How bad can the deformation space of an object be?” The answer seems to be: “Unless there is some a priori reason otherwise, the deformation space may be as bad as possible.” We show this for a number of important moduli spaces.
R. Vakil
semanticscholar   +1 more source

Algorithms in Singular [PDF]

Computer Science Journal of Moldova, 1996
Some algorithms for singularity theory and algebraic geometry The use of Grobner basis computations for treating systems of polynomial equations has become an important tool in many areas.
Hans Schonemann
doaj  

Hexapods with Plane-Symmetric Self-Motions

Robotics, 2018
A hexapod is a parallel manipulator where the platform is linked with the base by six legs, which are anchored via spherical joints. In general, such a mechanical device is rigid for fixed leg lengths, but, under particular conditions, it can perform a ...
Georg Nawratil
doaj   +1 more source

Homotopy finiteness of some DG categories from algebraic geometry [PDF]

Journal of the European Mathematical Society (Print), 2013
In this paper, we prove that the bounded derived category $D^b_{coh}(Y)$ of coherent sheaves on a separated scheme $Y$ of finite type over a field $\mathrm{k}$ of characteristic zero is homotopically finitely presented.
A. Efimov
semanticscholar   +1 more source

The geometry of the generalized algebraic Riccati equation and of the singular Hamiltonian system [PDF]

Linear and Multilinear Algebra, 2018
This paper analyzes the properties of the solutions of the generalized continuous algebraic Riccati equation from a geometric perspective. This analysis reveals the presence of a subspace that may provide an appropriate degree of freedom to stabilize the system in the related optimal control problem even in cases where the Riccati equation does not ...
Ntogramatzidis, Lorenzo, Ferrante, A.
openaire   +3 more sources

Some results of algebraic geometry over Henselian rank one valued fields [PDF]

, 2014
We develop geometry of affine algebraic varieties in $$K^{n}$$Kn over Henselian rank one valued fields K of equicharacteristic zero. Several results are provided including: the projection $$K^{n} \times {\mathbb {P}}^{m}(K) \rightarrow K^{n}$$Kn×Pm(K)→Kn
K. Nowak
semanticscholar   +1 more source