sidekick/TODO.md

Goals

TODO

• SAT:

  • merge all clause vectors into one
  • remove all simplifications at level 0
  • addition of clauses: should be much simpler

• explicit lifecycle for SAT atoms (dead/assigned/in-heap)

• simplify addition of clauses:

  • do not simplify at level 0
  • steps on addition:
    1. internalize all atoms (dead -> in-heap)
    2. unit-propagate/do nothing/add clause
    3. remove clause on backtracking if not at level 0

• merge Solver_types.ml with Internal.ml

• make CC work on QF_UF

  • internalize terms on the fly (backtrackable)
  • basic notion of activity (of subterms) for ite (and recfuns, later)?

• redo_down_to_level_0 should actually redo down to base_level

• add CC.add_rw_step t u work, where t-->u (remove t from sig table, should have almost 0 overhead after that)

  • use it for

• notion of value (V_true,V_false,V_custom, + maybe undefined some day)

• write theory of datatypes (without acyclicity) with local case splits + value + injectivity

• design evaluation system (guards + eval:(term -> value) option in custom TC)

• compilation of rec functions to defined constants

• theory of defined constants relying on congruence closure + evaluation of guards of each case

• datatype acyclicity check

• Shostak theory of eq-ℚ

• abstract domain propagation in CC

• domain propagation (intervals) for ℚ arith

• full ℚ theory: shostak + domains + if-sat simplex

Main goals

• Add a backend to send proofs to dedukti
  • First, pure resolution proofs
  • Then, require theories to output lemma proofs for dedukti (in some format yet to be decided)
• Allow to plug one's code into boolean propagation
  • react upon propagation (possibly by propagating more, or side-effect)
  • more advanced/specific propagation (2-clauses)?
  • implement 'constraints' (see https://www.lri.fr/~conchon/TER/2013/3/minisat.pdf )

Long term goals

• max-sat/max-smt
• coq proofs ?

Done

• theory of boolean constructs (on the fly Tseitin using local clauses)
  • test Sat_solver.add_clause and new_atom behavior upon backtracking → when we backtrack an atom, its Tseitin encoding should be removed
  • NOTE: clauses should never be added twice (or else: what if a clause is added, removed (but not filtered from watched lits) then re-added? duplicate?)
• backtrackable addition of clauses/atoms in Sat solver
• remove tseitin lib
• typing and translation Ast -> Term (from mc2?)
• main executable for SMT solver
• base types (Term, Lit, …)
• theory combination
• basic design of theories