Epimorphisms between 2–bridge link groups
نویسندگان
چکیده
We give a systematic construction of epimorphisms between 2–bridge link groups. Moreover, we show that 2–bridge links having such an epimorphism between their link groups are related by a map between the ambient spaces which only have a certain specific kind of singularity. We show applications of these epimorphisms to the character varieties for 2–bridge links and π1 –dominating maps among 3–manifolds.
منابع مشابه
Knot Group Epimorphisms, II
We consider the relations ≥ and ≥p on the collection of all knots, where k ≥ k (respectively, k ≥p k) if there exists an epimorphism πk → πk of knot groups (respectively, preserving peripheral systems). When k is a torus knot, the relations coincide and k must also be a torus knot; we determine the knots k that can occur. If k is a 2-bridge knot and k ≥p k, then k is a 2-bridge knot with determ...
متن کاملEffect of Link Slab on Seismic Response of Two Span Straight and Skew Bridges
Highway bridges are frequently constructed as simple span structures with steel or concrete girders and a cast-in-place concrete deck, spanning from one pier to another. At each end of the simple span deck, a joint is provided for deck movement due to temperature, shrinkage, and creep. Bridge deck joints are expensive and pose many problems with regard to bridge maintenance. Elimination of deck...
متن کاملErgodicity and Mixing of Noncommuting Epimorphisms
We study mixing properties of epimorphisms of a compact connected finite-dimensional abelian group X . In particular, we show that a set F , |F | > dimX , of epimorphisms of X is mixing iff every subset of F of cardinality (dimX)+1 is mixing. We also construct examples of free nonabelian groups of automorphisms of tori which are mixing, but not mixing of order 3, and show that, under some irred...
متن کاملA GALOIS THEORY FOR MONOIDS Dedicated to Manuela Sobral on the occasion of her seventieth birthday
We show that the adjunction between monoids and groups obtained via the Grothendieck group construction is admissible, relatively to surjective homomorphisms, in the sense of categorical Galois theory. The central extensions with respect to this Galois structure turn out to be the so-called special homogeneous surjections. Introduction An action of a monoid B on a monoid X can be de ned as a mo...
متن کاملJu n 20 01 The many faces of cyclic branched coverings of 2 - bridge knots and links ∗
We discuss 3-manifolds which are cyclic coverings of the 3-sphere, branched over 2-bridge knots and links. Different descriptions of these manifolds are presented: polyhedral, Heegaard diagram, Dehn surgery and coloured graph constructions. Using these descriptions, we give presentations for their fundamental groups, which are cyclic presentations in the case of 2-bridge knots. The homology gro...
متن کامل