Any form of constraint solving tech. SAT solvers (used in hardware-synthesis, software verification, math proofs, etc.), Mixed Integer Solvers (usually sold for

Any form of constraint solving tech. SAT solvers (used in hardware-synthesis, software verification, math proofs, etc.), Mixed Integer Solvers (usually sold for tens of thousands of dollars) that are used for hardcore optimization problems, Google's Operations Research toolkit (OR-tools), etc. Unlike most algorithms, these things are general purpose, they can solve any* NP-complete problem (*usually in a useful amount of time). My manager refers to these things as "Machine Reasoning" in contrast with "Machine Learning", since they start from the rules instead of from examples.