  Energy and direction are tow basic properties of a vector. A discrete signal
is a vector in nature. RIP of compressive sensing can not show the direction
information of a signal but show the energy information of a signal. Hence, RIP
is not complete. Orthogonal matrices can preserve angles and lengths.
Preservation of length can show energies of signals like RIP do; and
preservation of angle can show directions of signals. Therefore, Restricted
Conformal Property (RCP) is proposed according to preservation of angle. RCP
can show the direction of a signal just as RIP shows the energy of a signal.
RCP is important supplement and development of RIP. Tow different proofs of RCP
are given, namely, RCP_JL and RCP_IP.
