This volume contains the proceedings of the 10th International Seminar on - lational Methods in Computer Science (RelMiCS 10) and the 5th International Workshop on Applications of Kleene Algebra (AKA 5). The joint conference took place in Frauenwo ..rthon an Island in Lake Chiem in Bavaria,April 7-April 11, 2008. Its purpose was to bring together researchers various subdisciplines of computer science, mathematics and related ?elds who use the calculus of - lations and/or Kleene algebra as methodological and conceptual tools in their work. This conference is the joint continuation of two di?erent strands of meetings. The seminars of the RelMiCS series were held in Schloss Dagstuhl (Germany) in January 1994, Parati (Brazil) in July 1995, Hammamet (Tunisia) in January 1997, Warsaw (Poland) in September 1998, Qu' ebec (Canada) in January 2000, and Oisterwijk (The Netherlands) in October 2001. The meeting on Appli- tions of Kleene Algebra started as a workshop, also held in Schloss Dagstuhl, in February2001.Tojointhesetwothemesinoneconferencewasmainlymotivated by the substantial common interests and overlap of the two communities.
Over the years this has led to fruitful interactions and openened new and interesting researchdirections.Jointmeetings havebeenheldinMalente(Germany)in May 2003, in St. Catherines (Canada) in February 2005 and in Manchester (UK) in August/September 2006. This volume contains 28 contributions by researchersfrom all overthe world.