let m be non empty Element of NAT ; for x, y being Point of (REAL-NS 1)
for i being Element of NAT st 1 <= i & i <= m holds
(reproj i,(0. (REAL-NS m))) . (x + y) = ((reproj i,(0. (REAL-NS m))) . x) + ((reproj i,(0. (REAL-NS m))) . y)
let x, y be Point of (REAL-NS 1); for i being Element of NAT st 1 <= i & i <= m holds
(reproj i,(0. (REAL-NS m))) . (x + y) = ((reproj i,(0. (REAL-NS m))) . x) + ((reproj i,(0. (REAL-NS m))) . y)
let i be Element of NAT ; ( 1 <= i & i <= m implies (reproj i,(0. (REAL-NS m))) . (x + y) = ((reproj i,(0. (REAL-NS m))) . x) + ((reproj i,(0. (REAL-NS m))) . y) )
assume A1:
( 1 <= i & i <= m )
; (reproj i,(0. (REAL-NS m))) . (x + y) = ((reproj i,(0. (REAL-NS m))) . x) + ((reproj i,(0. (REAL-NS m))) . y)
consider q1 being Element of REAL , z1 being Element of REAL m such that
A2:
( x = <*q1*> & z1 = 0. (REAL-NS m) & (reproj i,(0. (REAL-NS m))) . x = (reproj i,z1) . q1 )
by PDIFF_1:def 6;
consider q2 being Element of REAL , z2 being Element of REAL m such that
A3:
( y = <*q2*> & z2 = 0. (REAL-NS m) & (reproj i,(0. (REAL-NS m))) . y = (reproj i,z2) . q2 )
by PDIFF_1:def 6;
consider q12 being Element of REAL , z12 being Element of REAL m such that
A4:
( x + y = <*q12*> & z12 = 0. (REAL-NS m) & (reproj i,(0. (REAL-NS m))) . (x + y) = (reproj i,z12) . q12 )
by PDIFF_1:def 6;
A5:
0. (REAL-NS m) = 0* m
by REAL_NS1:def 4;
reconsider qq1 = <*q1*> as Element of REAL 1 by FINSEQ_2:118;
reconsider qq2 = <*q2*> as Element of REAL 1 by FINSEQ_2:118;
x + y = qq1 + qq2
by REAL_NS1:2, A2, A3;
then A6:
x + y = <*(q1 + q2)*>
by RVSUM_1:29;
((reproj i,(0. (REAL-NS m))) . x) + ((reproj i,(0. (REAL-NS m))) . y) =
((reproj i,(0* m)) . q1) + ((reproj i,(0* m)) . q2)
by A2, A3, A5, REAL_NS1:2
.=
(reproj i,(0* m)) . (q1 + q2)
by A1, Th13
;
hence
(reproj i,(0. (REAL-NS m))) . (x + y) = ((reproj i,(0. (REAL-NS m))) . x) + ((reproj i,(0. (REAL-NS m))) . y)
by A6, A4, A5, FINSEQ_1:97; verum