theorem Th67: :: MESFUN15:65

for f being PartFunc of REAL,REAL
for a, b being Real st a < b & ].a,b.] c= dom f & f is_left_ext_Riemann_integrable_on a,b & abs f is_left_ext_Riemann_integrable_on a,b holds
max- f is_left_ext_Riemann_integrable_on a,b