set x = the Point of M;
reconsider f = the carrier of M --> the Point of M as Function of M,M ;
take
f
; f is contraction
take
1 / 2
; ALI2:def 1 ( 0 < 1 / 2 & 1 / 2 < 1 & ( for x, y being Point of M holds dist ((f . x),(f . y)) <= (1 / 2) * (dist (x,y)) ) )
thus
( 0 < 1 / 2 & 1 / 2 < 1 )
; for x, y being Point of M holds dist ((f . x),(f . y)) <= (1 / 2) * (dist (x,y))
let z, y be Point of M; dist ((f . z),(f . y)) <= (1 / 2) * (dist (z,y))
( f . z = the Point of M & f . y = the Point of M )
by FUNCOP_1:7;
then A1:
dist ((f . z),(f . y)) = 0
by METRIC_1:1;
dist (z,y) >= 0
by METRIC_1:5;
hence
dist ((f . z),(f . y)) <= (1 / 2) * (dist (z,y))
by A1; verum