If the solution is unique then there is a logical path to it, though maybe not one feasible to discover for an agent with bounded time and (especially for humans) bounded working memory. Consider the search tree of a…
I think neel_k was referring to the fact that when a DPLL or CDCL solver concludes UNSAT you can take the trace its backtracking activity and rewrite it from the bottom up as a resolution refutation. So in this sense…
Sudoku may be a poor example for illustrating some of the overarching points of this series of blog posts, which I take to be that modern SAT solvers are, as someone described them in a previous thread, "little diamonds…
This sounds like Crook's Algorithm (https://www.ams.org/notices/200904/tx090400460p.pdf), which is a perfectly reasonable thing to do, especially for pencil-and-paper puzzle solving since pigeonhole inferences are easy…
It's easy to see why this puzzle has no solution. Looking at columns 4-6 we see that none of the digits 1,5,6 can occur in cells G4,H4,I4 or G6,H6,I6. So some permutation of these digits occupies G5,H5,I5 and all digits…
It can be done with just depth first search, but if you want it to be fast you can go pretty far down the rabbit hole. The details of your representation, your heuristics, and the kinds of constraint propagation you…
If the solution is unique then there is a logical path to it, though maybe not one feasible to discover for an agent with bounded time and (especially for humans) bounded working memory. Consider the search tree of a…
I think neel_k was referring to the fact that when a DPLL or CDCL solver concludes UNSAT you can take the trace its backtracking activity and rewrite it from the bottom up as a resolution refutation. So in this sense…
Sudoku may be a poor example for illustrating some of the overarching points of this series of blog posts, which I take to be that modern SAT solvers are, as someone described them in a previous thread, "little diamonds…
This sounds like Crook's Algorithm (https://www.ams.org/notices/200904/tx090400460p.pdf), which is a perfectly reasonable thing to do, especially for pencil-and-paper puzzle solving since pigeonhole inferences are easy…
It's easy to see why this puzzle has no solution. Looking at columns 4-6 we see that none of the digits 1,5,6 can occur in cells G4,H4,I4 or G6,H6,I6. So some permutation of these digits occupies G5,H5,I5 and all digits…
It can be done with just depth first search, but if you want it to be fast you can go pretty far down the rabbit hole. The details of your representation, your heuristics, and the kinds of constraint propagation you…