let F1, F2 be Function of (Closed-Interval-TSpace 0 ,1),(Closed-Interval-TSpace a,b); ( ( for s being Point of (Closed-Interval-TSpace 0 ,1)
for r, r1, r2 being real number st s = r & r1 = t1 & r2 = t2 holds
F1 . s = ((1 - r) * r1) + (r * r2) ) & ( for s being Point of (Closed-Interval-TSpace 0 ,1)
for r, r1, r2 being real number st s = r & r1 = t1 & r2 = t2 holds
F2 . s = ((1 - r) * r1) + (r * r2) ) implies F1 = F2 )
assume A20:
for s being Point of (Closed-Interval-TSpace 0 ,1)
for r, r1, r2 being real number st s = r & r1 = t1 & r2 = t2 holds
F1 . s = ((1 - r) * r1) + (r * r2)
; ( ex s being Point of (Closed-Interval-TSpace 0 ,1) ex r, r1, r2 being real number st
( s = r & r1 = t1 & r2 = t2 & not F2 . s = ((1 - r) * r1) + (r * r2) ) or F1 = F2 )
assume A21:
for s being Point of (Closed-Interval-TSpace 0 ,1)
for r, r1, r2 being real number st s = r & r1 = t1 & r2 = t2 holds
F2 . s = ((1 - r) * r1) + (r * r2)
; F1 = F2
for s being Point of (Closed-Interval-TSpace 0 ,1) holds F1 . s = F2 . s
hence
F1 = F2
by FUNCT_2:113; verum