Hopf Spaces Research Articles

Digital Hopf Spaces and Their Duals

In this article, we study the fundamental notions of digital Hopf and co‐Hopf spaces based on pointed digital images. We show that a digital Hopf space, a digital associative Hopf space, a digital Hopf group, and a digital commutative Hopf space are unique up to digital homotopy type; that is, there is only one possible digital Hopf structure up to digital homotopy type on the underlying digital image. We also establish an equivalent condition for a digital image to be a digital Hopf space and investigate the difference between ordinary topological co‐Hopf spaces and their digital counterparts by showing that any digital co‐Hopf space is a digitally contractible space focusing on deep‐learning methods in imaging science.

On the Digital Pontryagin Algebras

In the current study, we explore digital homology modules, and investigate their fundamental properties on (pointed) digital images as one of the developments of symmetries. We also examine pointed digital Hopf spaces and base point preserving digital Hopf functions between pointed digital Hopf spaces with suitable digital multiplications, and explore the digital primitive homology classes, digital Pontryagin algebras on digital Hopf spaces as a symmetric phenomenon in mathematics and computer science.

Algebraic loop structures on algebra comultiplications

Abstract In this paper, we study the algebraic loop structures on the set of Lie algebra comultiplications. More specifically, we investigate the fundamental concepts of algebraic loop structures and the set of Lie algebra comultiplications which have inversive, power-associative and Moufang properties depending on the Lie algebra comultiplications up to all the possible quadratic and cubic Lie algebra comultiplications. We also apply those notions to the rational cohomology of Hopf spaces.

Near-rings on digital Hopf groups

In this paper, we study the digital Hopf groups and the digital Hopf functions between digital Hopf spaces with digital multiplications, and construct a near-ring structure on the set of all pointed digital homotopy classes of digital Hopf functions between pointed digital Hopf groups. We also investigate a near-ring homomorphism between near-rings based on the pointed digital Hopf groups to find a new method of how to give answers to the original problems or how to get a new information out of old ones more effectively.

Some Characterizations of Hopf Group on Fuzzy Topological Spaces

In this paper, some fundamental concepts are given relating to fuzzy topological spaces. Then it is shown that there is a contravariant functor from the category of the pointed fuzzy topological spaces to the category of groups and homomorphisms. Also the fuzzy topological spaces which are Hopf spaces are investigated and it is shown that a pointed fuzzy toplogical space having the same homotopy type as an Hopf group is itself an Hopf group.

On the cohomology of highly connected covers of finite Hopf spaces

Relying on the computation of the André–Quillen homology groups for unstable Hopf algebras, we prove that if the mod p cohomology of both the fiber and the base in an H-fibration is finitely generated as algebra over the Steenrod algebra, then so is the mod p cohomology of the total space. In particular, the mod p cohomology of the n-connected cover of a finite H-space is always finitely generated as algebra over the Steenrod algebra.

Deconstructing Hopf spaces

We characterize Hopf spaces with finitely generated cohomology as an algebra over the Steenrod algebra. We “deconstruct” the original space into an H-space Y with finite mod p cohomology and a finite number of p-torsion Eilenberg-Mac Lane spaces. We give a precise description of homotopy commutative H-spaces in this setting.

Splitting off rational parts in homotopy types

It is known algebraically that any abelian group is a direct sum of a divisible group and a reduced group (see Theorem 21.3 of [L. Fuchs, Infinite Abelian Groups, vol. I, Academic Press, New York–London, 1970]). In this paper, conditions to split off rational parts in homotopy types from a given space are studied in terms of a variant of Hurewicz map, say ρ ¯ : [ S Q n , X ] → H n ( X ; Z ) and generalised Gottlieb groups. This yields decomposition theorems on rational homotopy types of Hopf spaces, T-spaces and Gottlieb spaces, which has been known in various situations, especially for spaces with finiteness conditions.

A∞-method in Lusternik–Schnirelmann category

To clarify the method behind (Iwase, Bull. Lond. Math. Soc. 30 (1998), 623–634), a generalisation of Berstein–Hilton Hopf invariants is defined as ‘higher Hopf invariants’. They detect the higher homotopy associativity of Hopf spaces and are studied as obstructions not to increase the LS category by one by attaching a cone. Under a condition between dimension and LS category, a criterion for Ganea's conjecture on LS category is obtained using the generalised higher Hopf invariants, which yields the main result of (Iwase, Bull. Lond. Math. Soc. 30 (1998), 623–634) for all the cases except the case when p=2. As an application, conditions in terms of homotopy invariants of the characteristic maps are given to determine the LS category of sphere-bundles-over-spheres. Consequently, a closed manifold M is found not to satisfy Ganea's conjecture on LS category and another closed manifold N is found to have the same LS category as its ‘punctured submanifold’ N−{P}, P∈N . But all examples obtained here support the conjecture in (Iwase, Bull. Lond. Math. Soc. 30 (1998), 623–634).

Maps between small Hopf spaces

Maps between small Hopf spaces

Self homotopy groups of Hopf spaces with at most three cells

We prove that if X is aconnected H-space with at most three cells of positive dimension, then the self homotopy set of X becomes a group relative to the binary operation induced from any multiplication on X, and we determine it's group structure in some cases.

Adjoint action of a finite loop space. II

Adjoint actions of compact simply connected Lie groups are studied by Kozima and the second author based on the series of studies on the classification of simple Lie groups and their cohomologies. At odd primes, the first author showed that there is a homotopy theoretic approach that will prove the results of Kozima and the second author for any 1-connected finite loop spaces. In this paper, we use the rationalization of the classifying space to compute the adjoint actions and the cohomology of classifying spaces assuming torsion free hypothesis, at the prime 2. And, by using Browder's work on the Kudo–Araki operations Q1 for homotopy commutative Hopf spaces, we show the converse for general 1-connected finite loop spaces, at the prime 2. This can be done because the inclusion j: G > BAG satisfies the homotopy commutativity for any non-homotopy commutative loop space G.

Involution and anti involution on Hopf spaces

Involution and anti involution on Hopf spaces

Adjoint action of a finite loop space

Adjoint actions of compact simply connected Lie groups are studied by Kozima and the second author based on the series of studies on the classification of simple Lie groups and their cohomologies. At odd primes, the first author showed that there is a homotopy theoretic approach that will prove the results of Kozima and the second author for any 1connected finite loop spaces. In this paper, we use the rationalisation of the classifying space to compute the adjoint actions and the cohomology of classifying spaces assuming torsion free hypothesis, at the prime 2. And, by using Browder’s work on the Kudo-Araki operations Q1 for homotopy commutative Hopf spaces, we show the converse for general 1-connected finite loop spaces, at the prime 2. This can be done because the inclusion j : G → BΛG satisfies the homotopy commutativity for any non-homotopy commutative loop space G.

Book Review: The homology of Hopf spaces

Book Review: The homology of Hopf spaces