# IC3¶

IC3/PDR is a recent technique by Aaron Bradley. IC3 alone can falsify and prove properties. To enable nothing but IC3, run

kind2 --enable IC3 <file>


The challenge when lifting IC3 to infinite state systems is the pre-image computation. If the input problem is in linear integer arithmetic, Kind 2 performs a fast approximate quantifier elimination. Otherwise, the quantifier elimination is delegated to an SMT solver, which is at this time only possible with Z3.

## Options¶

--ic3_qe {cooper|Z3} (default cooper) – select the quantifier elimination strategy: cooper (default) for the built-in approximate method, Z3 to delegate to the SMT solver. If the problem is not in linear integer arithmetic, cooper falls back to Z3.

--ic3_check_inductive <bool> (default true) – Check if a blocking clause is inductive and communicate it as an invariant to concurrent verification engines.

--ic3_block_in_future  <bool> (default true) – Block each clause not only in the frame it was discovered, but also in all higher frames.

--ic3_fwd_prop_non_gen <bool> (default true) – Attempt forward propagation of clauses before inductive generalization.

--ic3_fwd_prop_ind_gen <bool> (default true) – Inductively generalize clauses after forward propagation.

--ic3_fwd_prop_subsume <bool> (default true) – Check syntactic subsumption of forward propagated clauses