Lambda: A Mathematica package for operator product expansions in vertex algebras

We give an introduction to the Mathematica package Lambda, designed for calculating λ-brackets in both vertex algebras, and in SUSY vertex algebras. This is equivalent to calculating operator product expansions in two-dimensional conformal field theory. The syntax of λ  -brackets is reviewed, and some simple examples are shown, both in component notation, and in N=1N=1 superfield notation.Program summaryProgram title: LambdaCatalogue identifier: AEHF_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHF_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GNU General Public LicenseNo. of lines in distributed program, including test data, etc.: 18 087No. of bytes in distributed program, including test data, etc.: 131 812Distribution format: tar.gzProgramming language: MathematicaComputer: See specifications for running Mathematica V7 or above.Operating system: See specifications for running Mathematica V7 or above.RAM: Varies greatly depending on calculation to be performed.Classification: 4.2, 5, 11.1.Nature of problem: Calculate operator product expansions (OPEs) of composite fields in 2d conformal field theory.Solution method: Implementation of the algebraic formulation of OPEs given by vertex algebras, and especially by λ-brackets.Running time: Varies greatly depending on calculation requested. The example notebook provided takes about 3 s to run.