376
ESPACES PRÉHILBERTIENS
= 111 j(t) - P(t) dtl < llJ(2n)ll,"' 11 T~(t) dt
-1
/f=t2
- (2n)! _ 1 /f=t2
= llf( 2 n)lloo llT: 112 = llf( 2 n)lloo X _n_
(2n)!
n
(2n)!
22n-l ·