theorem
for
f being
PartFunc of
REAL,
REAL for
a,
b being
Real st
[.a,b.[ c= dom f &
f is_right_ext_Riemann_integrable_on a,
b holds
for
c,
d being
Real st
a <= c &
c < d &
d <= b holds
(
f is_right_ext_Riemann_integrable_on c,
d & (
d < b implies
ext_right_integral (
f,
c,
d)
= integral (
f,
c,
d) ) )