arXiv subjects

Ivan Limonchenko

Publications and source records attributed to Ivan Limonchenko.

24 records · Page 2Linked to original sources

arXiv2018

Topology of polyhedral products over simplicial multiwedges

We prove that certain conditions on multigraded Betti numbers of a simplicial complex $K$ imply existence of a higher Massey product in cohomology of a moment-angle-complex $\mathcal Z_K$, which contains a unique element (a strictly defined product). Using the simplicial multiwedge construction, we find a family $\mathcal{F}$ of polyhedral products being smooth closed manifolds such that for any $l,r\geq 2$ there exists an $l$-connected manifold $M\in\mathcal F$ with a nontrivial strictly defined $r$-fold Massey product in $H^{*}(M)$. As an application to homological algebra, we determine a wide class of triangulated spheres $K$ such that a nontrivial higher Massey product of any order may exist in Koszul homology of their Stanley--Reisner rings. As an application to rational homotopy theory, we establish a combinatorial criterion for a simple graph $Γ$ to provide a (rationally) formal generalized moment-angle manifold $\mathcal Z_{P}^{J}=(D^{2j_{i}},S^{2j_{i}-1})^{\partial P^*}$, $J=(j_{1},\ldots,j_m)$ over a graph-associahedron $P=P_Γ$ and compute all the diffeomorphism types of formal moment-angle manifolds over graph-associahedra.

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arXiv2018

Embeddings of moment-angle manifolds and sequences of Massey products

We show that for any face $F$ of a simple polytope $P$ the canonical equivariant homeomorphisms $h_P:\,\mathcal Z_P\to\mathcal Z_{K_P}$ and $h_F:\,\mathcal Z_F\to\mathcal Z_{K_F}$ are linked in a pentagonal commutative diagram with the maps of moment-angle manifolds and moment-angle-complexes, induced by a face embedding $i_{F,P}:\,F\to P$ and a simplicial embedding $Φ_{F,P}:\,K_F\to K_{F,P}\to K_P$, where $K_{F,P}$ is the full subcomplex of $K_P$ on the same vertex set as $Φ_{F,P}(K_F)$. We introduce the explicit constructions of the maps $i_{F,P}$, $Φ_{F,P}$ and show that a polytope $P$ is flag if and only if the induced embedding $\hat{i}_{F,P}:\,\mathcal Z_{F}\to\mathcal Z_P$ of moment-angle manifolds has a retraction and thus induces a split ring epimorphism in cohomology for any face $F\subset P$. As the applications of these results we obtain the sequences $\{P^n\}$ of flag simple polytopes such that there exists a nontrivial $k$-fold Massey product in $H^*(\mathcal Z_{P^n})$ with $k\to\infty$ as $n\to\infty$ and, moreover, the existence of a nontrivial $k$-fold Massey product in $H^*(\mathcal Z_{P^n})$ implies existence of a nontrivial $k$-fold Massey product in $H^*(\mathcal Z_{P^l})$ for any $l>n$.

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arXiv2018

Calabi-Yau hypersurfaces and SU-bordism

Batyrev constructed a family of Calabi-Yau hypersurfaces dual to the first Chern class in toric Fano varieties. Using this construction, we introduce a family of Calabi-Yau manifolds whose SU-bordism classes generate the special unitary bordism ring $\varOmega^{SU}\otimes\mathbb{Z}[\frac{1}{2}]\cong\mathbb{Z}[\frac{1}{2}][y_{i}\colon i\ge 2]$. We also describe explicit Calabi-Yau representatives for multiplicative generators of the SU-bordism ring in low dimensions.

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arXiv2017

Moment-angle manifolds, 2-truncated cubes and Massey operations

We construct a family of manifolds, one for each $n\geq 2$, having a nontrivial Massey $n$-product in their cohomology. These manifolds turn out to be smooth closed 2-connected manifolds with a compact torus action called moment-angle manifolds $\mathcal Z_P$, whose orbit spaces are simple $n$-dimensional polytopes $P$ obtained from a $n$-cube by a sequence of truncations of faces of codimension 2 only (2-truncated cubes). Moreover, the polytopes $P$ are flag nestohedra but not graph-associahedra. We compute some bigraded Betti numbers $β^{-i,2(i+1)}(Q)$ for an associahedron $Q$ in terms of its graph structure and relate it to the structure of the loop homology (Pontryagin algebra) $H_{*}(Ω\mathcal Z_Q)$. We also study triple Massey products in $H^{*}(\mathcal Z_Q)$ for a graph-associahedron $Q$.

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arXiv2014

Stanley--Reisner rings of generalised truncation polytopes and their moment-angle manifolds

We consider simple polytopes $P=vc^{k}(Δ^{n_{1}}\times\ldots\timesΔ^{n_{r}})$, for $n_1\ge\ldots\ge n_r\ge 1,r\ge 1,k\ge 0$, that is, $k$-vertex cuts of a product of simplices, and call them {\emph{generalized truncation polytopes}}. For these polytopes we describe the cohomology ring of the corresponding moment-angle manifold $\mathcal Z_P$ and explore some topological consequences of this calculation. We also examine minimal non-Golodness for their Stanley--Reisner rings and relate it to the property of $\mathcal Z_P$ being a connected sum of sphere products.

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arXiv2011

Bigraded Betti numbers of some simple polytopes

The bigraded Betti numbers b^{-i,2j}(P) of a simple polytope P are the dimensions of the bigraded components of the Tor groups of the face ring k[P]. The numbers b^{-i,2j}(P) reflect the combinatorial structure of P as well as the topology of the corresponding moment-angle manifold \mathcal Z_P, and therefore they find numerous applications in combinatorial commutative algebra and toric topology. Here we calculate some bigraded Betti numbers of the type β^{-i,2(i+1)} for associahedra, and relate the calculation of the bigraded Betti numbers for truncation polytopes to the topology of their moment-angle manifolds. These two series of simple polytopes provide conjectural extrema for the values of b^{-i,2j}(P) among all simple polytopes P with the fixed dimension and number of vertices.

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