let f be FinSequence of REAL ; :: thesis: for a being Real st len f > 0 & a > 0 holds
( max (a * f) = a * (max f) & max_p (a * f) = max_p f )
let a be Real; :: thesis: ( len f > 0 & a > 0 implies ( max (a * f) = a * (max f) & max_p (a * f) = max_p f ) )
assume A1:
( len f > 0 & a > 0 )
; :: thesis: ( max (a * f) = a * (max f) & max_p (a * f) = max_p f )
A2:
len (a * f) = len f
by EUCLID_2:8;
A3:
dom (a * f) = dom f
by VALUED_1:def 5;
A4:
max_p (a * f) in dom (a * f)
by A1, A2, Def1;
then A5:
( 1 <= max_p (a * f) & max_p (a * f) <= len (a * f) )
by FINSEQ_3:27;
A6:
max (a * f) = a * (f . (max_p (a * f)))
by RVSUM_1:66;
max_p (a * f) in Seg (len f)
by A2, A5, FINSEQ_1:3;
then A7:
max_p (a * f) in dom f
by FINSEQ_1:def 3;
then A8:
f . (max_p (a * f)) <= f . (max_p f)
by A1, Def1;
A9:
a * (f . (max_p f)) = (a * f) . (max_p f)
by RVSUM_1:66;
A10:
a * (f . (max_p (a * f))) = (a * f) . (max_p (a * f))
by RVSUM_1:66;
A11:
max_p f in dom (a * f)
by A1, A3, Def1;
then
(a * f) . (max_p f) <= (a * f) . (max_p (a * f))
by A1, A2, Def1;
then
f . (max_p f) <= f . (max_p (a * f))
by A1, A9, A10, XREAL_1:70;
then A12:
f . (max_p f) = f . (max_p (a * f))
by A8, XXREAL_0:1;
max_p f in dom (a * f)
by A1, A3, Def1;
then A13:
(a * f) . (max_p (a * f)) >= (a * f) . (max_p f)
by A1, A2, Def1;
f . (max_p f) >= f . (max_p (a * f))
by A1, A7, Def1;
then
a * (f . (max_p f)) >= a * (f . (max_p (a * f)))
by A1, XREAL_1:66;
then A14:
(a * f) . (max_p (a * f)) = (a * f) . (max_p f)
by A9, A10, A13, XXREAL_0:1;
A15:
max_p (a * f) >= max_p f
by A1, A3, A4, A12, Def1;
max_p (a * f) <= max_p f
by A1, A2, A11, A14, Def1;
hence
( max (a * f) = a * (max f) & max_p (a * f) = max_p f )
by A6, A15, XXREAL_0:1; :: thesis: verum