When the user wants to strengthen a MIP with cutting planes and valid inequalities — deriving cover, clique, MIR, or Gomory cuts, writing separation routines, and adding them as user cuts or lazy constraints via Gurobi callbacks. Also use when the user mentions "valid inequalities," "cutting planes," "separation problem," "user cuts," "cover inequalities," "subtour elimination," or when a formulation needs exponentially many constraints generated on the fly. For callback mechanics beyond cuts, see gurobi-advanced-features; for formulation tightening, see integer-programming-techniques.
