Proof failures

Error: no contradiction was found.

The logical formula had no property in negative position or Gappa has discharged all of them, yet this was not sufficient to prove the formula.

{ x in [1,2] -> not x + 1 in [2,3] }
Error: no contradiction was found.

Error: some enclosures were not satisfied.

Only part of a conjunction of goals was proved to be true. Gappa was unable to prove some other expressions or formulas, which are displayed after the message.

{ x in [1,2] -> x + 1 in ? /\ x + 2 in [2,3] }
Warning: case split on x + 2 has not produced any interesting new result.
Results:
  x + 1 in [2, 3]
Error: some properties were not satisfied:
  BND(x + 2), best: [3, 4]