We investigate the exceptional set E-delta(X, h) associated with the asympt
otic formula for the number of primes in short intervals; see Section 1 for
the definition. We first obtain two results about the basic structure of t
his set, proving the inertia and decrease properties; see Theorem 1. Then w
e turn to estimates For the size of E-delta(X, h), showing that non-trivial
bounds for \E-delta(X,h)\ can be obtained when h(x) = x(theta) and 1/6 < t
heta < 7/12; see Theorem 2. (C) 2000 Academic Press.