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Samson Saneblidze

Publications and source records attributed to Samson Saneblidze.

At least 19 recordsLinked to original sources

On the bialgebra structure of the free loop homology

We introduce a commutative product of degree $-n$ on the homology $H_\ast(X)$ of an $n$-dimensional special cubical set $X$ and lift it on the free loop homology $H_\ast(\Lambda M)$ for $M=|X|$ to be the geometric realization. These products agree with the intersection and string topology products respectively when $M$ is an oriented closed manifold, and we establish the compatibility relation between the string topology product and the standard coproduct on $H_\ast(\Lambda M).$ Motivated by the above relationship we introduce the notion of loop bialgebra for differential graded coalgebras $C$ by means of the coHochschild complex $\Lambda C.$ We calculate the loop bialgebra structure for some spaces.

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Secondary cohomology operations and the loop space cohomology

Motivated by the loop space cohomology we construct the secondary operations on the cohomology $H^*(X; \mathbb{Z}_p)$ to be a Hopf algebra for a simply connected space $X.$ The loop space cohomology ring $H^*(\Omega X; \mathbb{Z}_p)$ is calculated in terms of generators and relations. This answers to A. Borel's decomposition of a Hopf algebra into a tensor product of the monogenic ones in which the heights of generators are determined by means of the action of the primary and secondary cohomology operations on $H^*(X;\mathbb{Z}_p).$ An application for calculating of the loop space cohomology of the exceptional group $F_4$ is given.

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Framed Matrices and $A_{\infty}$-Bialgebras

We complete the construction of the biassociahedra $KK$, construct the free matrad $\mathcal{H}_{\infty}$, realize $\mathcal{H}_{\infty}$ as the cellular chains of $KK,$ and define an $A_{\infty}$-bialgebra as an algebra over $\mathcal{H}_{\infty}.$ We construct the bimultiplihedra $JJ,$ construct the relative free matrad $r\mathcal{H}_{\infty}$ as a $\mathcal{H}_{\infty}$-bimodule, realize $r\mathcal{H}_{\infty}$ as the cellular chains of $JJ$, and define a morphism of $A_{\infty}$-bialgebras as a bimodule over $\mathcal{H}_{\infty}$. We prove that the homology of every $A_{\infty}$-bialgebra over a commutative ring with unity admits an induced $A_{\infty}$-bialgebra structure. We extend the Bott-Samelson isomorphism to an isomorphism of $A_{\infty}$-bialgebras and determine the $A_{\infty} $-bialgebra structure of $H_{\ast}\left( ΩΣX;\mathbb{Q}\right) $. For each $n\geq2$, we construct a space $X_{n}$ and identify an induced nontrivial $A_{\infty}$-bialgebra operation $ω_{2}^{n}: H^{\ast}\left(ΩX_{n};\mathbb{Z}_{2}\right) ^{\otimes2}\rightarrow H^{\ast}\left(ΩX_{n};\mathbb{Z}_{2}\right) ^{\otimes n}$.

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Comparing Diagonals on the Associahedra

We prove that the formula for the diagonal approximation $\Delta_{K}$ on J. Stasheff's $n$-dimensional associahedron $K_{n+2}$ derived by the current authors in 2004 agrees with the "magical formula" for the diagonal approximation $\Delta_{K}^{\prime}$ derived by Markl and Shnider in 2006, by Loday in 2011, and by Masuda, Thomas, Tonks, and Vallette in 2021.

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A combinatorial model for the path fibration

We introduce the abstract notion of a necklical set in order to describe a functorial combinatorial model of the path fibration over the geometric realization of a path connected simplicial set. In particular, to any path connected simplicial set $X$ we associate a necklical set $\widehat{\mathbfΩ}X$ such that its geometric realization $|\widehat{\mathbfΩ}X|$, a space built out of gluing cubical cells, is homotopy equivalent to the based loop space on $|X|$ and the differential graded module of chains $C_*(\widehat{\mathbfΩ}X)$ is a differential graded associative algebra generalizing Adams' cobar construction.

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A combinatorial model for the free loop fibration

We introduce the abstract notion of a closed necklical set in order to describe a functorial combinatorial model of the free loop fibration $ΩY\rightarrow ΛY\rightarrow Y$ over the geometric realization $Y=|X|$ of a path connected simplicial set $X.$ In particular, to any path connected simplicial set $X$ we associate a closed necklical set $\widehat{\mathbfΛ}X$ such that its geometric realization $|\widehat{\mathbfΛ}X|$, a space built out of gluing "freehedrical" and "cubical" cells, is homotopy equivalent to the free loop space $ΛY$ and the differential graded module of chains $C_*(\widehat{\mathbfΛ}X)$ generalizes the coHochschild chain complex of the chain coalgebra $C_\ast(X).$

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Filtered Hirsch Algebras

Motivated by the cohomology theory of loop spaces, we consider a special class of higher order homotopy commutative differential graded algebras and construct the filtered Hirsch model for such an algebra $A$. When $x\in H(A)$ with $\mathbb{Z}$ coefficients and $x^{2}=0,$ the symmetric Massey products $% \langle x\rangle ^{n}$ with $n\geq 3$ have a finite order (whenever defined). However, if $\Bbbk $ is a field of characteristic zero, $\langle x\rangle ^{n}$ is defined and vanishes in $H(A\otimes \Bbbk )$ for all $n$. If $p$ is an odd prime, the Kraines formula $\langle x\rangle ^{p}=-β\mathcal{P}_{1}(x)$ lifts to $H^{\ast }(A\otimes {\mathbb{Z}}_{p}).$ Applications of the existence of polynomial generators in the loop homology and the Hochschild cohomology with a $G$-algebra structure are given.

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Morphisms of A-infinity Bialgebras and Applications

We define the notion of a relative matrad and realize the free relative matrad as a free H_\infty-bimodule structure on cellular chains of bimultiplihedra JJ={JJ_{n,m} = JJ_{m,n}}. We define a morphism G:A => B of A_\infty-bialgebras as a bimodule over H_\infty and prove that the homology of every A_\infty-bialgebra over a commutative ring with unity admits an induced A_\infty-bialgebra structure. We extend the Bott-Samelson isomorphism to an isomorphism of A_\infty-bialgebras and identify the A_\infty-bialgebra structure of H_*(ΩΣX; Q). For each n>1, we construct a space X_n and identify an induced nontrivial A_\infty-bialgebra operation ω_2^n : H^*(ΩX_n; Z_2)^2 -> H^*(ΩX_n; Z_2)^n.

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The loop cohomology of a space with the polynomial cohomology algebra

Given a simply connected space $X$ with the cohomology $H^*(X;{\mathbb Z}_2)$ to be polynomial, we calculate the loop cohomology algebra $H^*(ΩX;{\mathbb Z}_2)$ by means of the action of the Steenrod cohomology operation $Sq_1$ on $H^*(X;{\mathbb Z}_2).$ As a consequence we obtain that $H^*(ΩX;{\mathbb Z}_2)$ is the exterior algebra if and only if $Sq_1$ is multiplicatively decomposable on $H^{\ast}(X;{\mathbb Z}_2).$ The last statement in fact contains a converse of a theorem of A. Borel.

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On the homology theory of the closed geodesic problem

Let $ΛX$ be the free loop space on a simply connected finite $CW$-complex $X$ and $β_{i}(ΛX;\Bbbk)$ be the cardinality of a minimal generating set of $H^{i}(ΛX;\Bbbk)$ for $\Bbbk$ to be a commutative ring with unit. The sequence $ β_{i}(ΛX;\Bbbk) $ grows unbounded if and only if $\tilde {H}^{\ast}(X;\Bbbk)$ requires at least two algebra generators. This in particular answers to a long standing problem whether a simply connected closed smooth manifold has infinitely many geometrically distinct closed geodesics in any Riemannian metric.

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Matrads, Biassociahedra and A_{\infty}-Bialgebras

We introduce the notion of a matrad M = {M_{n,m}} whose submodules M_{*,1} and M_{1,*} are non-Sigma operads. We define the free matrad H_{\infty} generated by a singleton in each bidegree (m,n) and realize H_{\infty} as the cellular chains on biassociahedra KK_{n,m} = KK_{m,n}, of which KK_{n,1} = KK_{1,n} is the associahedron K_{n}. We construct the universal enveloping functor from matrads to PROPs and define an A_{\infty}-bialgebra as an algebra over H_{\infty}.

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On the homotopy classification of spaces by the fixed loop space homology

Let $R\subseteq \Bbb Q$ be a subring of the rationals and let $p$ be the least prime (if none, $p=\infty $) which is not invertible in $R.$ For an $R$-local $r$-connected $CW$-complex $X$ of dimension $\leq \min(r+2p-3,rp-1), r\geq 1, $ a complete homotopy invariant is constructed in terms of the loop space homology $H_*(ΩX).$ This allows us to classify all such $R$-local spaces up to homotopy with a fixed loop space homology.

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On the Betti numbers of a loop space

Let $A$ be a special homotopy G-algebra over a commutative unital ring $\Bbbk$ such that both $H(A)$ and $\operatorname{Tor}_{i}^{A}(\Bbbk,\Bbbk)$ are finitely generated $\Bbbk$-modules for all $i$, and let $τ_{i}(A)$ be the cardinality of a minimal generating set for the $\Bbbk$-module $\operatorname{Tor}_{i}^{A}(\Bbbk,\Bbbk).$ Then the set ${τ_{i}(A)} $ is unbounded if and only if $\tilde{H}(A)$ has two or more algebra generators. When $A=C^{\ast}(X;\Bbbk)$ is the simplicial cochain complex of a simply connected finite $CW$-complex $X,$ there is a similar statement for the "Betti numbers" of the loop space $ΩX.$ This unifies existing proofs over a field $\Bbbk$ of zero or positive characteristic.

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On the homotopy classification of maps

We establish certain conditions which imply that a map $f:X\to Y$ of topological spaces is null homotopic when the induced integral cohomology homomorphism is trivial; one of them is: $H^*(X)$ and $π_*(Y)$ have no torsion and $H^*(Y)$ is polynomial.

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The bitwisted Cartesian model for the free loop fibration

Using the notion of truncating twisting function from a simplicial set to a cubical set a special, bitwisted, Cartesian product of these sets is defined. For the universal truncating twisting function, the (co)chain complex of the corresponding bitwisted Cartesian product agrees with the standard Cartier (Hochschild) chain complex of the simplicial (co)chains. The modelling polytopes $F_n$ are constructed. An explicit diagonal on $F_n$ is defined and a multiplicative model for the free loop fibration $ΩY\to ΛY\to Y$ is obtained. As an application we establish an algebra isomorphism $H^*(ΛY;\mathbb{Z}) \approx S(U)\otimes Λ(s^{_{-1}}U)$ for the polynomial cohomology algebra $H^*(Y;\mathbb{Z})=S(U).$

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On derived categories and derived functors

For an abelian category, a category equivalent to its derived category is constructed by means of specific projective (injective) multicomplexes, the so-called homological resolutions.

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The Biderivative and A_\infty-bialgebras

An A_\infty-bialgebra is a DGM H equipped with structurally compatible operations {ω^{j,i} : H^{\otimes i} --> H^{\otimes j}} such that (H,ω^{1,i}) is an A_\infty-algebra and (H,ω^{j,1}) is an A_\infty-coalgebra. Structural compatibility is controlled by the biderivative operator Bd, defined in terms of two kinds of cup products on certain cochain algebras of pemutahedra over the universal PROP U = End(TH).

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