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Tom Lada

Publications and source records attributed to Tom Lada.

9 recordsLinked to original sources
arXiv2014

Homotopy derivations

We define a strong homotopy derivation of (cohomological) degree k of a strong homotopy algebra over an operad P. This involves resolving the operad obtained from P by adding a generator with "derivation relations". For a wide class of Koszul operads P, in particular Ass and Lie, we describe the strong homotopy derivations by coderivations and show that they are closed under the Lie bracket. We show that symmetrization of a strong homotopy derivation of an A-infinity algebra yields a strong homotopy derivation of the symmetrized L-infinity algebra. We give examples of strong homotopy derivations generalizing inner derivations.

math.AT↗
arXiv2009

Examples of Homotopy Lie Algebras

We look at two examples of homotopy Lie algebras (also known as L_{\infty} algebras) in detail from two points of view. We will exhibit the algebraic point of view in which the generalized Jacobi expressions are verified by using degree arguments and combinatorics. A second approach using the nilpotency of Grassmann-odd differential operators Δto verify the homotopy Lie data is shown to produce the same results.

math.QA↗
arXiv2005

Symmetric Brace Algebras

We develop a symmetric analog of brace algebras and discuss the relation of such algebras to $L_{\infty}$-algebras. We give an alternate proof that the category of symmetric brace algebras is isomorphic to the category of pre-Lie algebras. As an application, symmetric braces are used to describe transfers of strongly homotopy structures. We then explain how these symmetric brace algebras may be used to examine the $L_{\infty}$-algebras that result from a particular gauge theory for massless particles of high spin.

math.QA↗
arXiv2002

Noether's variational theorem II and the BV formalism

We review the basics of the Lagrangian approach to field theory and recast Noether's Second Theorem formulated in her language of dependencies using a slight modernization of terminology and notation. We then present the Cattaneo-Felder sigma model and work out the Noether identities or dependencies for this model. We review the description of the Batalin-Vilkovisky formalism and show explicitly how the anti-ghosts encode the Noether identities in this example.

math.QA↗
arXiv2001

Sh-Lie algebras Induced by Gauge Transformations

The physics of ``particles of spin $\leq 2$'' leads to representations of a Lie algebra $Ξ$ of gauge parameters on a vector space $Φ$ of fields. Attempts to develop an analogous theory for spin $>2$ have failed; in fact, there are claims that such a theory is impossible (though we have been unable to determine the hypotheses for such a `no-go' theorem). This led BBvD [burgers:diss,BBvd:three,BBvD:probs] to generalize to `field dependent parameters' in a setting where some analysis in terms of smooth functions is possible. Having recognized the resulting structure as that of an sh-lie algebra ($L_\infty$-algebra), we have now reproduced their structure entirely algebraically, hopefully shedding some light on what is going on.

math.QA↗
arXiv1994

Strongly homotopy Lie algebras

The present paper can be thought of as a continuation of the paper "Introduction to sh Lie algebras for physicists" by T. Lada and J. Stasheff (International Journal of Theoretical Physics Vol. 32, No. 7 (1993), 1087--1103, appeared also as preprint hep-th/9209099) which provided an exposition of the basic ingredients of the theory of strongly homotopy Lie algebras sufficient for the underpinnings of the physically relevant examples. We demonstrate the `strong homotopy' analog of the usual relation between Lie and associative algebras and investigate the universal enveloping algebra functor emerging as the left adjoint of the symmetrization functor. We show that the category of homotopy associative algebras carries a natural monoidal structure such that the universal enveloping algebra is a unital coassociative cocommutative coalgebra with respect to this monoidal structure. The last section is concerned with the relation between homotopy modules and weak homotopy maps. The present paper is complementary to what currently exists in the literature, both physical and mathematical.

hep-th↗
arXiv1992

Introduction to sh Lie algebras for physicists

Closed string field theory leads to a generalization of Lie algebra which arose naturally within mathematics in the study of deformations of algebraic structures. It also appeared in work on higher spin particles \cite{BBvD}. Representation theoretic analogs arose in the mathematical analysis of the Batalin-Fradkin-Vilkovisky approach to constrained Hamiltonians. A major goal of this paper is to see the relevant formulas, especially in closed string field theory, as a generalization of those for a differential graded Lie algebra, hopefully describing the mathematical essentials in terms accessible to {\it physicists}.

hep-th↗