This volume contains the proceedings of the Fourth Asian Computing Science Conference (ASIAN98), held December 8{10, 1998, in Manila, the Philippines. The previous three ASIAN conferences were also published as Lecture Notes in Computer Science, Volumes 1023 (Bangkok, 1995), 1179 (Singapore, 1996), and 1345 (Kathmandu, 1997). Initiated in 1995 by the Asian Institute of Technology in partnership with INRIAandUNU, the ASIANconferenceseriesaimsatprovidingaforuminAsia fortheexchangeofthemostrecentresearchideasandresultsincomputerscience andinformationtechnology.Whileeachyearfeaturesseveralemphasizedthemes, the 1998 conference focuses on the research areas of (1) formal reasoning and veri cation, (2) programminglanguages, (3) dataand knowledgerepresentation, and (4) networking and Web computing. There were 43 submissions to the conference, out of which 17 were chosen for presentation and inclusion in this proceedings. The papers were submitted fromAustralia, Brazil, China, France, Germany, India, Italy, Japan, Korea, New Zealand, the Philippines, Russia, Singapore, Spain, Switzerland, Taiwan, Th- land, the United Kindom, and the United States of America. The program c- mittee meeting was held virtually over the Internet. The selection was nalized after a fteen-day period of lively discussion. Each paper was carefully reviewed and received at least three reports. In addition to 17 highly selective papers, this year's conference also features a keynotespeechby Jeannette M.Wing (CarnegieMellonUniversity)onFormal Methods: Past, Present, andFuture, twoinvitedtalksbySusumuHayashi(Kobe University) on Testing Proofs by Examples and Claude Kirchner (INRIA) on The RewritingCalculus as a Semantics ofELAN, and two tutorials by Tomasz Janowski(UNU/IIST)onSemanticsandLogicforProvableFault-Tolerance and R.K. Shyamasundar (TIFR) onMobile Computation: Calculus and

This volume presents the proceedings of the Sixth International Conference on Rewriting Techniques and Applications, RTA-95, held in Kaiserslautern, Germany in April 1995.
The 27 full revised papers were selected from a total of 87 submissions. In addition there are 9 system descriptions and two problem sets, one contributed by Mark E. Stickel and Hantao Zhang and another by Nachum Dershowitz, Jean-Pierre Jouannaud and Jan Willem Klop.
The volume addresses all current aspects of rewriting techniques and their applications and thus defines the state-of-the-art in this active field of research.