=+2.15. On the field $o in (0, 1] define P( A) to be 1 or 0 according as there does or does not exist some positive €4 (depending on A) such that A contains the interval ( ¿, ¿ + €4]. Show that P is finitely but not countably additive. No such example is possible for the field Go in S® (Theorem 2.3).