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Homotopy algebras via resolutions of operads

Markl, Martin — 2000

Proceedings of the 19th Winter School "Geometry and Physics"

Summary: All algebraic objects in this note will be considered over a fixed field k of characteristic zero. If not stated otherwise, all operads live in the category of differential graded vector spaces over k . For standard terminology concerning operads, algebras over operads, etc., see either the original paper by [“The geometry of iterated loop spaces”, Lect. Notes Math. 271 (1972; Zbl 0244.55009)], or an overview [, “La renaissance des opérads”, Sémin. Bourbaki 1994/95, Exp. No. 792, Asterisque...

Free loop spaces and cyclohedra

Markl, Martin — 2003

Proceedings of the 22nd Winter School "Geometry and Physics"

It is well-known that a based space is of the weak homotopy type of a loop space iff it is a grouplike algebra over an A -operad. The classical model for such an operad consists of Stasheff’s associahedra. The present paper describes a similar recognition principle for free loop spaces. Let 𝒫 be an operad, M a 𝒫 -module and U a 𝒫 -algebra. An M -trace over U consists of a space V and a module homomorphism T : M End U , V over the operad homomorphism 𝒫 End U given by the algebra structure on U . Let 𝒞 1 be the little 1-cubes...

Towards one conjecture on collapsing of the Serre spectral sequence

Markl, Martin — 1990

Proceedings of the Winter School "Geometry and Physics"

[For the entire collection see Zbl 0699.00032.] A fibration F E B is called totally noncohomologuous to zero (TNCZ) with respect to the coefficient field k, if H * ( E ; k ) H * ( F ; k ) is surjective. This is equivalent to saying that π 1 ( B ) acts trivially on H * ( F ; k ) and the Serre spectral sequence collapses at E 2 . S. Halperin conjectured that for c h a r ( k ) = 0 and F a 1-connected rationally elliptic space (i.e., both H * ( F ; 𝒬 ) and π * ( F ) 𝒬 are finite dimensional) such that H * ( F ; k ) vanishes in odd degrees, every fibration F E B is TNCZ. The author proves this being the case...

Deformations and the koherence

Markl, Martin — 1994

Proceedings of the Winter School "Geometry and Physics"

The cotangent cohomology of and [Trans. Am. Math. Soc. 128, 41-70 (1967; Zbl 0156.27201)] is known for its ability to control the deformation of the structure of a commutative algebra. Considering algebras in the wider sense to include coalgebras, bialgebras and similar algebraic structures such as the Drinfel’d algebras encountered in the theory of quantum groups, one can model such objects as models for an algebraic theory much in the sense of [Proc. Natl. Acad. Sci. USA 50, 869-872 (1963)]....

Formal computations in low-dimensional topology: links and group presentations

Markl, Martin — 1993

Proceedings of the Winter School "Geometry and Physics"

The author describes the moduli space of Sullivan models of 2-skeletal spaces and complements of links as quotients of spaces of derivations of finitely generated free Lie algebras L by the action of a subgroup of automorphisms of L . For recall, a 2-skeletal space is a path connected space S satisfying H 3 ( S ; ) = 0 and dim H * ( S , ) < . The paper contains as an application a complete description of the Lie algebras associated to the fundamental groups of complements of two-component links in terms of their Milnor numbers....

Homotopy diagrams of algebras

Markl, Martin — 2002

Proceedings of the 21st Winter School "Geometry and Physics"

The paper is concerned with homotopy concepts in the category of chain complexes. It is part of the author’s program to translate [ and , Homotopy invariant algebraic structures on topological spaces, Lect. Notes Math. 347, Springer-Verlag (1973; Zbl 0285.55012)] from topology to algebra.In topology the notion of operad extracts the essential algebraic information contained in the following example (endomorphism operad).The endomorphism operad X of a based space X consists of the family X ( j ) ...

On the compactification of configuration spaces

Markl, MartinStasheff, James D. — 1998

Proceedings of the 17th Winter School "Geometry and Physics"

The article contains a list of 7 problems related to operads and configuration spaces. Problems 1-2 are about the compactification of configuration spaces (homology and Koszulness, geometric decompositions). Problems 3-4 are about configuration spaces related to knot invariants, their geometry and Koszulness. Problems 5 to 7 are related to (operadically defined) traces and cyclic homology.

Distributive laws and Koszulness

Martin Markl — 1996

Annales de l'institut Fourier

Distributive law is a way to compose two algebraic structures, say 𝒰 and 𝒱 , into a more complex algebraic structure 𝒲 . The aim of this paper is to understand distributive laws in terms of operads. The central result says that if the operads corresponding respectively to 𝒰 and 𝒱 are Koszul, then the operad corresponding to 𝒲 is Koszul as well. An application to the cohomology of configuration spaces is given.

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