(x1 - x2 <= 0) /\ (x2 - x3 <= 0) /\ (x3 - x1 <= -1)             => UNSAT (x1=x2, x2=x3, x1<x3)
(x1 - x2 < 0) /\ (x2 - x3 <= 0) /\ (x3 - x1 <= 0)               => UNSAT (idem)
(x1 - x2 <= 0) /\ (x2 - x3 <= 0) /\ (x3 - x1 <= 0)              => SAT

(x1 - x2 <= 0) /\ (x2 - x3 <= 0) /\ (x3 - x1 <= -1)             => UNSAT (x1=x2, x2=x3, x1<x3)
(x1 - x2 < 0) /\ (x2 - x3 <= 0) /\ (x3 - x1 <= 0)               => UNSAT (idem)
(x1 - x2 <= 0) /\ (x2 - x3 <= 0) /\ (x3 - x1 <= 0)              => SAT
((x1 - x2 <= 0) \/ (x1 - x2 <= 0)) /\ ((x2 - x3 <= 0) \/ (x2 - x3 <= 0)) /\ ((x3 - x1 < 0) \/ (x3 - x1 <= 0))   => UNSAT
((x1 - x2 <= 0) \/ (x1 - x2 <= 0)) /\ ((x2 - x3 <= 0) \/ (x2 - x3 <= 0)) /\ ((x3 - x1 < 0) \/ (x3 - x1 < 0))    => SAT

Add examples of diff theory.
Add examples of diff theory.
