A universal space for plus-constructions
نویسندگان
چکیده
We exhibit a two-dimensional, acyclic, Eilenberg–Mac Lane space W such that, for every space X, the plus-construction X+ with respect to the largest perfect subgroup of π1(X) coincides, up to homotopy, with the W -nullification of X; that is, the natural map X → X+ is homotopy initial among maps X → Y where the based mapping space map∗(W,Y ) is weakly contractible. Furthermore, we describe the effect of W -nullification for any acyclic W , and show that some of its properties imply, in their turn, the acyclicity of W .
منابع مشابه
Central extensions and generalized plus-constructions
We describe the effect of homological plus-constructions on the homotopy groups of Eilenberg-MacLane spaces in terms of universal central extensions.
متن کاملStrongly universal hashing and identification codes via channels
This paper shows that-almost strongly universal classes of hash functions can yield better explicit constructions of identiication codes via channels (ID codes) and identiication plus transmission codes (IT codes) than the previous explicit constructions of Verd u and Wei.
متن کاملUniversal Approximator Property of the Space of Hyperbolic Tangent Functions
In this paper, first the space of hyperbolic tangent functions is introduced and then the universal approximator property of this space is proved. In fact, by using this space, any nonlinear continuous function can be uniformly approximated with any degree of accuracy. Also, as an application, this space of functions is utilized to design feedback control for a nonlinear dynamical system.
متن کاملConvertible limited (multi-) verifier signature: new constructions and applications
A convertible limited (multi-) verifier signature (CL(M)VS) provides controlled verifiability and preserves the privacy of the signer. Furthermore, limited verifier(s) can designate the signature to a third party or convert it into a publicly verifiable signature upon necessity. In this proposal, we first present a generic construction of convertible limited verifier signature (CLVS) into which...
متن کاملThe RedBlue Adaptive Universal Constructions
We present the family of RedBlue algorithms, a collection of universal wait-free constructions for linearizable shared objects in an asynchronous shared-memory distributed system with n processes. The algorithms are adaptive and improve upon previous algorithms in terms of their time and/or space complexity. The first of the algorithms is of theoretical interest only; it achieves better time co...
متن کامل