let y1, y2 be Real; :: thesis: ( ex Intf being PartFunc of REAL,REAL st
( dom Intf = ].a,b.] & ( for x being Real st x in dom Intf holds
Intf . x = integral (f,x,b) ) & Intf is_right_convergent_in a & y1 = lim_right (Intf,a) ) & ex Intf being PartFunc of REAL,REAL st
( dom Intf = ].a,b.] & ( for x being Real st x in dom Intf holds
Intf . x = integral (f,x,b) ) & Intf is_right_convergent_in a & y2 = lim_right (Intf,a) ) implies y1 = y2 )

assume ex Intf1 being PartFunc of REAL,REAL st
( dom Intf1 = ].a,b.] & ( for x being Real st x in dom Intf1 holds
Intf1 . x = integral (f,x,b) ) & Intf1 is_right_convergent_in a & y1 = lim_right (Intf1,a) ) ; :: thesis: ( for Intf being PartFunc of REAL,REAL holds
( not dom Intf = ].a,b.] or ex x being Real st
( x in dom Intf & not Intf . x = integral (f,x,b) ) or not Intf is_right_convergent_in a or not y2 = lim_right (Intf,a) ) or y1 = y2 )

then consider Intf1 being PartFunc of REAL,REAL such that
A3: dom Intf1 = ].a,b.] and
A4: for x being Real st x in dom Intf1 holds
Intf1 . x = integral (f,x,b) and
Intf1 is_right_convergent_in a and
A5: y1 = lim_right (Intf1,a) ;
assume ex Intf2 being PartFunc of REAL,REAL st
( dom Intf2 = ].a,b.] & ( for x being Real st x in dom Intf2 holds
Intf2 . x = integral (f,x,b) ) & Intf2 is_right_convergent_in a & y2 = lim_right (Intf2,a) ) ; :: thesis: y1 = y2
then consider Intf2 being PartFunc of REAL,REAL such that
A6: dom Intf2 = ].a,b.] and
A7: for x being Real st x in dom Intf2 holds
Intf2 . x = integral (f,x,b) and
Intf2 is_right_convergent_in a and
A8: y2 = lim_right (Intf2,a) ;
now :: thesis: for x being Element of REAL st x in dom Intf1 holds
Intf1 . x = Intf2 . x
let x be Element of REAL ; :: thesis: ( x in dom Intf1 implies Intf1 . x = Intf2 . x )
assume A9: x in dom Intf1 ; :: thesis: Intf1 . x = Intf2 . x
hence Intf1 . x = integral (f,x,b) by A4
.= Intf2 . x by A3, A6, A7, A9 ;
:: thesis: verum
end;
hence y1 = y2 by ; :: thesis: verum