Otten has more efficient solvers in "Part 3: Tableau and Connection Provers" but i find the sequent proofs much easier to understand (which makes sense, the "natural" in "Natural Deduction" means something like "intuitive" as used in IT.)
https://en.wikipedia.org/wiki/Natural_deduction
Otten has more efficient solvers in "Part 3: Tableau and Connection Provers" but i find the sequent proofs much easier to understand (which makes sense, the "natural" in "Natural Deduction" means something like "intuitive" as used in IT.)
https://en.wikipedia.org/wiki/Natural_deduction