The International Symposium on Practical Aspects of Declarative Languages (PADL) is a forum for researchers and practioners to present original work emphasizing novel applications and implementation techniques for all forms of declarativeconcepts,includingfunctional,logic,constraints,etc.Declarativel- guages build on sound theoretical foundations to provide attractive frameworks for application development. These languages have been successfully applied to a wide array of di?erent real-world situations, including database management, active networks, software engineering, decision support systems, or music c- position; whereas new developments in theory and implementation have opened up new application areas. Inversely, applications often drive the progress in the theory and implementation of declarative systems, as well as bene?t from this progress. The 7th PADL Symposium was held in Long Beach, California on January 10-11, 2005, and was co-located with ACM's Principles of Programming L- guages(POPL).From36 submitted papers,the ProgramCommittee selected 17 papers for presentation at the symposium, based upon at least three reviews for eachpaper,providedfromProgramCommitteemembersandadditionalreferees.Two invited talks were presented at the conference: one by Norman R- sey (Harvard University) entitled "Building the World from First Principles: Declarative Machine Descriptions and Compiler Construction"; and a second by Saumya Debray (University of Arizona) entitled "Code Compression." Following what has become a tradition in PADL symposia, the Program Committee selected one paper to receive the "Most Practical Paper" award. This year the paper judged the best in terms of practicality, originality, and claritywas"AProvablyCorrectCompilerforE?cientModelCheckingofMobile Processes,"byPingYang,YifeiDong,C.R.Ramakrishnan,andScottA.Smolka.

The International Symposium on Practical Aspects of Declarative Languages (PADL) is a forum for researchers and practioners to present original work emphasizing novel applications and implementation techniques for all forms of declarativeconcepts,includingfunctional,logic,constraints,etc.Declarativel- guages build on sound theoretical foundations to provide attractive frameworks for application development. These languages have been successfully applied to a wide array of di?erent real-world situations, including database management, active networks, software engineering, decision support systems, or music c- position; whereas new developments in theory and implementation have opened up new application areas. Inversely, applications often drive the progress in the theory and implementation of declarative systems, as well as bene?t from this progress. The 7th PADL Symposium was held in Long Beach, California on January 10-11, 2005, and was co-located with ACM's Principles of Programming L- guages(POPL).From36 submitted papers,the ProgramCommittee selected 17 papers for presentation at the symposium, based upon at least three reviews for eachpaper,providedfromProgramCommitteemembersandadditionalreferees.Two invited talks were presented at the conference: one by Norman R- sey (Harvard University) entitled "Building the World from First Principles: Declarative Machine Descriptions and Compiler Construction"; and a second by Saumya Debray (University of Arizona) entitled "Code Compression." Following what has become a tradition in PADL symposia, the Program Committee selected one paper to receive the "Most Practical Paper" award. This year the paper judged the best in terms of practicality, originality, and claritywas"AProvablyCorrectCompilerforE?cientModelCheckingofMobile Processes,"byPingYang,YifeiDong,C.R.Ramakrishnan,andScottA.Smolka.