(*
 * Original HOL4 code for satisfiability testing by Mike Gordon (2004)
 * DIMACS cnf parsing code improved by Ken Friis Larsen (2004?)
 * MiniSat proof reconstruction and HOL Light port by Hasan Amjad (2005-6)
 * Implicit definitional CNF and minor improvements by John Harrison (2006-7)
 * zChaff to MiniSat proof translator by Hasan Amjad (2007)
 *)
