Before revision: On the unit circle In general, elements of L2 on the unit circle are given by whereas elements of H2 are given by The projection from L2 to H2 (by setting when ) is orthogonal.
After revision: On the unit circle In general, elements of L2 on the unit circle are given by whereas elements of H2 are given by The projection from L2 to H2 (by setting an = 0 when n < 0 ) is orthogonal.