The formula is $\partial e=\left(a{d}_e\right)b+{\sum }_{i=0}^{\infty }\left(B_i\right)/i!{\left(a{d}_e\right)}^i(b-a)$, with ∂a + 1/2 [a,a] = 0 and ∂b + 1/2 [b,b] = 0, where a, b and e in degrees -1, -1 and 0 are the free generators of a completed free graded Lie algebra L[a,b,e]. The coefficients are defined by $x/(e^x-1)={\sum }_{n=0}^{\infty }Bₙ/n!xⁿ$. The theorem is that ∙ this formula for ∂ on generators extends to a derivation of square zero on L[a,b,e]; ∙ the formula for ∂e is unique satisfying the first property, once given the formulae for ∂a and ∂b, along with the condition that the “flow” generated by e moves a to b in unit...

Let $M$ be any compact simply-connected oriented $d$-dimensional smooth manifold and let $𝔽$ be any field. We show that the Gerstenhaber algebra structure on the Hochschild cohomology on the singular cochains of $M$, $H{H}^{*}(S^{*}\left(M\right),S^{*}\left(M\right))$, extends to a Batalin-Vilkovisky algebra. Such Batalin-Vilkovisky algebra was conjectured to exist and is expected to be isomorphic to the Batalin-Vilkovisky algebra on the free loop space homology on $M$, $H_{*+d}\left(LM\right)$ introduced by Chas and Sullivan. We also show that the negative cyclic cohomology $H{C}_{-}^{*}\left(S^{*}\left(M\right)\right)$...

Given a principal ideal domain $R$ of characteristic zero, containing 1/2, and a two-cone $X$ of appropriate connectedness and dimension, we present a sufficient algebraic condition, in terms of Adams-Hilton models, for the Hopf algebra $FH(\Omega X;R)$ to be isomorphic with the universal enveloping algebra of some $R$-free graded Lie algebra; as usual, $F$ stands for free part, $H$ for homology, and $\Omega$ for the Moore loop space functor.

L’algèbre de Pontryagin d’un espace $K$-elliptique vérifie le théorème d’Auslander-Buchsbaum-Serre. Nous donnons ici plusieurs caractérisations des espaces $K$-elliptiques tels que gldim($H_{*}(\Omega S;K))\<\infty$ et lorsque $(S,K)$ est dans le domaine d’Anick. Nous introduisons aussi une suite spectrale “impaire des $ℰ\mathrm{xt}$” et complétons les résultats obtenus par A. Murillo dans le cas rationnel.

We define a new $E_{\infty }$ operad based on surfaces with foliations which contains $E_k$ suboperads. We construct CW models for these operads and provide applications of these models by giving actions on Hochschild complexes (thus making contact with string topology), by giving explicit cell representatives for the Dyer-Lashof-Cohen operations for the 2-cubes and by constructing new Ω spectra. The underlying novel principle is that we can trade genus in the surface representation vs. the dimension k of the little...

Un des problèmes historiques de la théorie homotopique des espaces est de mesurer l’effet de l’attachement d’une cellule au niveau des groupes d’homotopie. Le problème de l’attachement inerte reste en particulier un problème ouvert. Nous donnons ici une réponse partielle à ce problème.