Quadrisecants give new lower bounds for the ropelength of a knot.
Qualgebras and knotted 3-valent graphs
This paper is devoted to new algebraic structures, called qualgebras and squandles. Topologically, they emerge as an algebraic counterpart of knotted 3-valent graphs, just like quandles can be seen as an "algebraization" of knots. Algebraically, they are modeled after groups with conjugation and multiplication/squaring operations. We discuss basic properties of these structures, and introduce and study the notions of qualgebra/squandle 2-cocycles and 2-coboundaries. Knotted 3-valent graph invariants...
Quandle coverings and their Galois correspondence
This article establishes the algebraic covering theory of quandles. For every connected quandle Q with base point q ∈ Q, we explicitly construct a universal covering p: (Q̃,q̃̃) → (Q,q). This in turn leads us to define the algebraic fundamental group , where Adj(Q) is the adjoint group of Q. We then establish the Galois correspondence between connected coverings of (Q,q) and subgroups of π₁(Q,q). Quandle coverings are thus formally analogous to coverings of topological spaces, and resemble Kervaire’s...
Quantum invariants of links and 3-valent graphs in 3-manifolds
Quantum invariants of periodic links and periodic 3-manifolds
We give criteria for framed links and 3-manifolds to be periodic of prime order. As applications we show that the Poincaré sphere is of periodicity 2, 3, 5 only and the Brieskorn sphere Σ(2,3,7) is of periodicity 2, 3, 7 only.
Quantum link invariant from the Lie superalgebra .
Quantum mechanics and nonabelian theta functions for the gauge group SU(2)
We propose a direction of study of nonabelian theta functions by establishing an analogy between the Weyl quantization of a one-dimensional particle and the metaplectic representation on the one hand, and the quantization of the moduli space of flat connections on a surface and the representation of the mapping class group on the space of nonabelian theta functions on the other. We exemplify this with the cases of classical theta functions and of the nonabelian theta functions for the gauge group...
Quantum faithfully detects mapping class groups modulo center.
Quasi locally connected toposes.
Quasi-isometric maps and Floyd boundaries of relatively hyperbolic groups
We describe the kernel of the canonical map from the Floyd boundary of a relatively hyperbolic group to its Bowditch boundary. Using the Floyd completion we further prove that the property of relative hyperbolicity is invariant under quasi-isometric maps. If a finitely generated group admits a quasi-isometric map into a relatively hyperbolic group then is itself relatively hyperbolic with respect to a system of subgroups whose image under is situated within a uniformly bounded distance...
Quasipositivity and new knot invariants.
This is a survey (including new results) of relations ?some emergent, others established? among three notions which the 1980s saw introduced into knot theory: quasipositivity of a link, the enhanced Milnor number of a fibered link, and the new link polynomials. The Seifert form fails to determine these invariants; perhaps there exists an ?enhanced Seifert form? which does.
Quasipsherical knots with infinitely many ends.
Quelques remarques sur les diagrammes de Heegard
Quelques remarques sur les diagrammes de Heegard en grandes dimensions
Quelques théorèmes de géométrie à dimensions
Question de Whitehead et modules précroisés
Quotienten komplexer Mannigfaltigkeiten nach spiegelungsfreien Gruppen.
Quotients compacts des groupes ultramétriques de rang un
Soit l’ensemble des points d’un groupe algébrique semi-simple connexe de rang relatif un sur un corps local ultramétrique. Nous décrivons tous les sous-groupes discrets de type fini sans torsion de qui agissent proprement et cocompactement sur par multiplication à gauche et à droite. Nous montrons qu’après une petite déformation dans un tel sous-groupe agit encore librement, proprement discontinûment et cocompactement sur .
Quotients jacobiens d'applications polynomiales
Soit où et sont des applications polynomiales. Nous établissons le lien qui existe entre le polygone de Newton de la courbe réunion du discriminant et du lieu de non-propreté de et la topologie des entrelacs à l’infini des courbes affines et . Nous en déduisons alors des conséquences liées à la conjecture du jacobien.
Quotients of Coxeter complexes, fundamental groupoids and Regular Graphs.