Enable using fixedpoint.spacer.ctp=true
For each lemma L currently at level k, keep a model M that justifies
why L cannot be pushed to (k+1). L is not pushed while the model M
remains valid.
- removed bg_assertions. Incompatible with mbp in spacer
- removed unique number. Unused
- removed mk_and() and switched to ast_util:mk_and() instead
spacer_manager::mk_and() uses bool_rewriter to simplify the
conjunction
Controlled by fixedpoint.spacer.use_quanti_generalizer
measure cumulative time, number of invocations, and number of failed
SMT calls
Relaxing equality in a pattern: if a variable equals a numeral, relax with GE
pob::get_skolems() returns all skolems that might appear in the pob.
New skolems must be added above the largest index in that map,
even if they are not used in the pob itself.
pattern generalization should be done before the pattern is skolemized and
added into the new cube.
It is possible that a new instance of a quantified lemma is discovered
even though a quantified lemma it already known. In this case, the
instance should be added to a corresponding context, even though the
lemma is not new.
The algorithms implemented in the engine are described in the following papers
Anvesh Komuravelli, Nikolaj Bjørner, Arie Gurfinkel, Kenneth L. McMillan:
Compositional Verification of Procedural Programs using Horn Clauses over Integers and Arrays. FMCAD 2015: 89-96
Nikolaj Bjørner, Arie Gurfinkel:
Property Directed Polyhedral Abstraction. VMCAI 2015: 263-281
Anvesh Komuravelli, Arie Gurfinkel, Sagar Chaki:
SMT-Based Model Checking for Recursive Programs. CAV 2014: 17-34
