Description:

CSIsat reads a set of mathematical formulas that may combine variables,
addition, multiplication, comparisons (<,>, etc.), as well as boolean
expressions (and, or, not). It determines if it is possible to set the
variables to values so that the set of formulas are all simultaneously true
(if it can, then the set of formulas is "satisfiable").

More technically, CSIsat is an interpolating decision procedure for the
quantifier-free theory of rational linear arithmetic (LA) and equality with
uninterpreted function (EUF) symbols. This implementation combines the
efficiency of linear programming for solving the arithmetic part with the
efficiency of a SAT solver to reason about the boolean structure.