Fuzzy Soft Topology Based on Generalized Intersection and Generalized Union of Fuzzy Soft Sets

In this study, the generalized intersection and union operations of fuzzy soft set (FSS) are established on the basis of traditional FSS operations, which overcome the shortcomings of traditional FSS operations that do not meet De Morgan’s law, and a series of properties of generalized intersection and union operations of FSS are obtained. The fuzzy soft topology under generalized intersection and generalized union operation of FSSs is established. Finally, the topological construction of weak FSS and strong FSS is discussed, and the relationship between them and the topological construction of traditional FSS is obtained.

Topological violation of global symmetries in quantum gravity

We discuss a topological reason why global symmetries are not conserved in quantum gravity, at least when the symmetry comes from compactification of a higher form symmetry. The mechanism is purely topological and does not require any explicit breaking term in the UV Lagrangian. Local current conservation does not imply global charge conservation in a sum over geometries in the path integral. We explicitly consider the shift symmetry of an axion-like field which originates from the compactification of a p-form gauge field. Our topological construction is motivated by the brane/black-brane correspondence, brane instantons, and an idea that virtual black branes of a simple kind may be realized by surgery on spacetime manifolds.

PCPATCH

Effective relaxation methods are necessary for good multigrid convergence. For many equations, standard Jacobi and Gauß–Seidel are inadequate, and more sophisticated space decompositions are required; examples include problems with semidefinite terms or saddle point structure. In this article, we present a unifying software abstraction, PCPATCH, for the topological construction of space decompositions for multigrid relaxation methods. Space decompositions are specified by collecting topological entities in a mesh (such as all vertices or faces) and applying a construction rule (such as taking all degrees of freedom in the cells around each entity). The software is implemented in PETSc and facilitates the elegant expression of a wide range of schemes merely by varying solver options at runtime. In turn, this allows for the very rapid development of fast solvers for difficult problems.

Quantum singularity theory via cosection localization

We generalize the cosection localized Gysin map to intersection homology and Borel–Moore homology, which provides us with a purely topological construction of the Fan–Jarvis–Ruan–Witten invariants and some GLSM invariants.

Simulation and Analysis on Tooth Meshing Ease-Off Surface of Gears Based on Polynomial Topology Modification

Based on the principles of common-generating conjugation mapping of pinion-rank-gear meshing, the constructing of ease-off surface has been done by means of the topology modification of the 4-order polynomial surface. The simulation method of tooth surface mesh is purposed based on the ease-off surface. By analyzing topological structure characteristics of ease-off surface such as modification gradient curves, contact line-off and contact path-off, the meshing characteristics such as the contact area, the contact line and transmission error are determined. It is stated on the interaction relations of coefficients of the 4-order polynomial to the topological construction of surface. The methods for reconstruction and analysis of ease-off surface with considering axis misalignments are presented by the direct transformation of coordinate systems. Taking the topological construction of four kinds of surfaces as examples, characteristics parameters such as modification gradient of tooth surface, contact path and transmission errors are simulated. They are expounded on the corresponding parameters of controlling form and adjusting methods for tooth surface. These methods take goals of adjusting-modification and controlling-property for tooth surface mesh. It is improved and developed the meshing analysis method of ease-off surface of tooth. The presented method is liable to provide the basis data for the further loaded contact analysis of complicated tooth surface and the more direct technical for the 3-D topological optimization of tooth surface.

Introductory Lectures on Equivariant Cohomology

Equivariant cohomology is concerned with the algebraic topology of spaces with a group action, or in other words, with symmetries of spaces. First defined in the 1950s, it has been introduced into K-theory and algebraic geometry, but it is in algebraic topology that the concepts are the most transparent and the proofs are the simplest. One of the most useful applications of equivariant cohomology is the equivariant localization theorem of Atiyah–Bott and Berline–Vergne, which converts the integral of an equivariant differential form into a finite sum over the fixed point set of the group action, providing a powerful tool for computing integrals over a manifold. Because integrals and symmetries are ubiquitous, equivariant cohomology has found applications in diverse areas of mathematics and physics. Assuming readers have taken one semester of manifold theory and a year of algebraic topology, the book begins with the topological construction of equivariant cohomology, then develops the theory for smooth manifolds with the aid of differential forms. To keep the exposition simple, the equivariant localization theorem is proven only for a circle action. An appendix gives a proof of the equivariant de Rham theorem, demonstrating that equivariant cohomology can be computed using equivariant differential forms. Examples and calculations illustrate new concepts. Exercises include hints or solutions, making this book suitable for self-study.