- add check for lambdas similar to as-array in context of quantifiers. MBQI is not a decision procedure for this combination and can then incorrectly conclude satisfiabiltiy.
Scenario
The formula contains assertions
- bv = (map or (lambda ..) t)
- forall y (not (select bv (pair s y)))
Since bv is extensionally equal to a term that depends on a lambda, MBQI cannot just take the current finite approximation of bv when checking the quantifier for satisfiability.
this update enables new incremental linear axioms based on division terms.
It also consolidates some of the backtracking state in nla_core / emons to use stack traces instead of custom backtracking state.
- convert reduce-args to a simplifier. Currently exposed as reduce-args2 tactic until the old tactic code gets removed.
- bug fixes in model_reconstruction trail
- allow multiple defs to be added with same pool of removed formulas
- fix tracking of function symbols instead of expressions to filter replay
- add nla_divisions to track (cheap) divisibility lemmas.
-
- increase build version to 4.12.1. This prepares updated release for MacOs-11 build on x86
- move literal propagation mode in euf-egraph to a callback and traversal of equivalence class. Track antecedent by newest equality instead of root. This makes equality propagation to literals have similar behavior as in legacy solver and appears to result in a speedup (10% fewer conflicts on QF_UF/QG-classification/qg5/iso_icl478.smt2 in preliminary testing)
- fix interaction of pre-processing and assumptions. Pre-processing has to freeze assumption literals so they don't get eliminated. This is similar to dependencies that are already frozen.
This update includes an experimental feature to access a congruence closure data-structure after search.
It comes with several caveats as pre-processing is free to eliminate terms. It is therefore necessary to use a solver that does not eliminate the terms you want to track for congruence of. This is partially addressed by using SimpleSolver or incremental mode solving.
```python
from z3 import *
s = SimpleSolver()
x, y, z = Ints('x y z')
s.add(x == y)
s.add(y == z)
s.check()
print(s.root(x), s.root(y), s.root(z))
print(s.next(x), s.next(y), s.next(z))
```
other updates:
- change signature of advance_qhead to simplify call sites
- have model reconstruction replay work on a tail of dependent_expr state, while adding formulas to the tail.
log theory propagations with annotation "smt".
It allows tracking theory propagations (when used in conflicts) in the clause logs similar to the new core.
