This project is inspired by SMTCoq and aims to provide Lean tactics that discharge goals into SMT solvers. This project is in its early design/development phase and is not recommended for use.

lean-smt communicates with SMT solvers via the SMT-LIB textual interface. Therefore, it requires a supported SMT solver to be installed. Currently, lean-smt supports two SMT solvers:

• cvc5 (default).
• z3.

To use the lean-smt in your project. Add the following line to your list of dependencies in lakefile.lean:

require smt from git "https://github.com/ufmg-smite/lean-smt.git"@"main"

lean-smt comes with one main tactic, smt, that translates the current goal into an SMT query, sends the query to an SMT solver, and prints the result returned by the SMT solver. The tactic DOES NOT currently generate a proof term to discharge the goal.

To use the smt tactic, you just need to import the Smt library:

import Smt

theorem modus_ponens (p q : Prop) : p → (p → q) → q := by
  smt
  simp_all

For the theorem above, smt prints

goal: p → (p → q) → q

query:
(declare-const p Bool)
(declare-const q Bool)
(assert (not (=> p (=> (=> p q) q))))
(check-sat)

result: unsat

You can specify the SMT solver to use like so:

set_option smt.solver.kind "z3"

lean-smt assumes the specified SMT solver to be in the path. If that's not the case, you can specify the path to the SMT solver like so:

set_option smt.solver.path "path/to/z3"