Mathematical Structures in Computer Science Special Issue on Isomorphisms of Types and Invertibility of Lambda-Terms Guest Editors: Ralph Matthes and Sergei Soloviev, Toulouse Call for contributions The study of invertibility of lambda-terms and related subjects such as isomorphisms of types, retractions and subtyping takes an important place in type theory. It is related to number theory, algebra and category theory, and it has applications to information retrieval systems, automatic code generation, data transformation, coding and cryptography. This special issue is a continuation of the series opened by the special issue of MSCS on Isomorphisms of Types published in 2005 (vol. 15, no. 5, Oct. 2005). Partly it is intended as a post-proceedings of WIT2005, a "Types" workshop at IRIT, Toulouse http://www.irit.fr/zeno/WIT2005/, but the contributions are subject to normal refereeing procedure and not limited to the papers presented by the participants of that workshop. Deadlines Deadline for submissions: 6 December 2006 Author's notification: 4 April 2007 Special issue's publication: Winter 2007/Spring 2008 Submissions The submissions should be sent in PDF or Postscript to the guest editors via email: {matthes, soloviev}@irit.fr. Extended versions of work previously published in conference proceedings are eligible for submission but authors should make it clear how their submission improves upon the conference publication; in those cases where Cambridge University Press is not the publisher of the original conference proceedings, authors should take care to avoid infringing that publisher's copyright. Authors who wish to discuss potential submissions are encouraged to contact the guest editors. The Mathematical Structures in Computer Science journal's policy is to impose restrictions in advance neither on the number of papers nor their length. However, as the special issue will contain approximately 180 pages, it is anticipated that it will contain a mixture of papers of between 15 and 45 pages.