The Free On-line Dictionary of Computing (30 December 2018):

Subset-Equational Language

   (SEL) A declarative language for set processing by Bharat
   Jayaraman with subset and equational program clauses; pattern
   matching over sets (it supports efficient iteration over
   sets); annotations to say which functions distribute over
   union in which arguments (for point-wise/incremental
   computation over sets); defining transitive closures through
   circular constraints (implemented by mixed
   top-down/memoisation and bottom-up strategy);
   meta-programming and simple higher-order programming;
   modest user-interface including tracing.

   The SEL compiler, written in Quintus Prolog, generates
   WAM-like code, extended to deal with set-matching,
   memoisation, and the novel control structure of the
   language.  The run-time system is written in C.

   (ftp://ftp.cs.buffalo.edu/users/bharat/SEL2).

   E-mail: Bharat Jayaraman .

   ["Towards a Broader Basis for Logic Programming",
   B. Jayaraman, TR CS Dept, SUNY Buffalo, 1990].

   ["Set Abstraction in Functional and Logic Programming",
   F.S.K. Silbermann  et al, ACM Proc 1989].

   (1994-12-15)