@InProceedings{Niehren_et_al:1997,
      AUTHOR = {Niehren, Joachim and Müller, Martin and Podelski, Andreas},
      TITLE = {Inclusion Constraints over Non-Empty Sets of Trees},
      YEAR = {1997},
      BOOKTITLE = {7th International Joint Conference CAAP/ FASE. Theory and Practice of Software Development (TAPSOFT '97), April 14-18},
      NUMBER = {1214},
      PAGES = {217-231},
      EDITOR = {Bidoit, M. and Dauchet, M.},
      SERIES = {Lecture Notes in Computer Science},
      ADDRESS = {Lille, France},
      PUBLISHER = {Springer},
      URL = {ftp://ftp.ps.uni-sb.de/pub/papers/ProgrammingSysLab/ines97.ps.gz},
      ABSTRACT = {We present a new constraint system called Ines. Its constraints are conjunctions of inclusions $t_1subseteq t_2$ between first-order terms (without set operators) which are interpreted over non-empty sets of trees. The existing systems of set constraints can express Ines constraints only if they include negation. Their satisfiability problem is NEXPTIME-complete. We present an incremental algorithm that solves the satisfiability problem of Ines constraints in cubic time. We intend to apply Ines constraints for type analysis for a concurrent constraint programming language.},
      ANNOTE = {COLIURL : Niehren:1997:ICN.pdf Niehren:1997:ICN.ps}
}