activity
20042023
most citedHomological perturbation theory for algebras over operads

70 citations · 93 across the 11 of their papers we have counts for

collaborators

17 papers

math.AT2023

On exponential groups and Maurer-Cartan spaces

Alexander Berglund

The purpose of this note is to give a concise account of some fundamental properties of the exponential group and the Maurer-Cartan space associated to a complete dg Lie algebra. I…

math.AT2022★ 1 cited

Algebraic models for classifying spaces of fibrations

Alexander Berglund, Tomáš Zeman

We prove new structural results for the rational homotopy type of the classifying space of fibrations with fiber a simply connected finite CW-complex .…

math.AT2020

Characteristic classes for families of bundles

Alexander Berglund

The generalized Miller-Morita-Mumford classes of a manifold bundle with fiber depend only on the underlying -fibration, meaning the family of vector bundles formed by the…

math.AT2019★ 6 cited

A dg Lie model for relative homotopy automorphisms

Alexander Berglund, Bashar Saleh

We construct a dg Lie model for the universal cover of the classifying space of the grouplike monoid of homotopy automorphisms of a space that fix a given subspace.

math.AT2017★ 3 cited

Koszul A-infinity algebras and free loop space homology

Alexander Berglund, Kaj Börjeson

We introduce a notion of Koszul A-infinity algebra that generalizes Priddy's notion of a Koszul algebra and we use it to construct small A-infinity algebra models for Hochschild co…

math.AT2017

Hirzebruch L-polynomials and multiple zeta values

Alexander Berglund, Jonas Bergström

We express the coefficients of the Hirzebruch L-polynomials in terms of certain alternating multiple zeta values. In particular, we show that every monomial in the Pontryagin class…

math.AT2017

Rational models for automorphisms of fiber bundles

Alexander Berglund

Given a fiber bundle, we construct a differential graded Lie algebra model for the classifying space of the monoid of homotopy equivalences of the base covered by a fiberwise isomo…

math.AT2015

Free Loop Space Homology of Highly Connected Manifolds

Alexander Berglund, Kaj Börjeson

We calculate the homology of the free loop space of (n-1)-connected closed manifolds of dimension at most 3n-2 (n > 1), with the Chas-Sullivan loop product and loop bracket. Over a…

math.AT2014

Homotopic Hopf-Galois extensions revisited

Alexander Berglund, Kathryn Hess

In this article we revisit the theory of homotopic Hopf-Galois extensions introduced in arXiv:0902.3393v2 [math.AT], in light of the homotopical Morita theory of comodules establis…

math.AT2014

Homotopical Morita theory for corings

Alexander Berglund, Kathryn Hess

A coring (A,C) consists of an algebra A and a coalgebra C in the monoidal category of A-bimodules. Corings and their comodules arise naturally in the study of Hopf-Galois extension…

math.AT2014

Rational homotopy theory of automorphisms of manifolds

Alexander Berglund, Ib Madsen

We study the rational homotopy types of classifying spaces of automorphism groups of smooth simply connected manifolds of dimension at least five. We give dg Lie algebra models for…

math.AT2012

Homological stability of diffeomorphism groups

Alexander Berglund, Ib Madsen

In this paper we prove a stability theorem for block diffeomorphisms of 2d-dimensional manifolds that are connected sums of S^d x S^d. Combining this with a recent theorem of S. Ga…

math.AT2011★ 12 cited

Rational homotopy theory of mapping spaces via Lie theory for L-infinity algebras

Alexander Berglund

We calculate the higher homotopy groups of the Deligne-Getzler infinity-groupoid associated to a nilpotent L-infinity algebra. As an application, we present a new approach to the r…

math.AT2011

Koszul spaces

Alexander Berglund

We prove that a nilpotent space is both formal and coformal if and only if it is rationally homotopy equivalent to the derived spatial realization of a graded commutative Koszul al…

math.AT2009★ 70 cited

Homological perturbation theory for algebras over operads

Alexander Berglund

We extend homological perturbation theory to encompass algebraic structures governed by operads and cooperads. The main difficulty is to find a suitable notion of algebra homotopy…

math.CO2008

Shellability and the strong gcd-condition

Alexander Berglund

Shellability is a well-known combinatorial criterion for verifying that a simplicial complex is Cohen-Macaulay. Another notion familiar to commutative algebraists, but which has no…

math.AC2004★ 1 cited

Poincare' series of monomial rings

Alexander Berglund

Let R be the quotient of a polynomial ring over a field k by an ideal generated by monomials. We derive a formula for the multigraded Poincare' series of R, i.e., the generating fu…