向量范数性质 等价性质: l)-‖xCl1s‖xC|2⊥xC 2)‖xC|24‖xl1≤n‖xC 3)‖x1nsx|2s√n‖XC| 例如:x=∑x圳x=max{x}≤∑x向量范数性质 等价性质：  =    =      =  =        n i i i i n n i i x x x n n n n n x x x x x x x x x x x 1 1 1 1 2 1 1 1 | | || || max{| |} | | 1 || || 1 : 3) || || || || || || 2) || || || || || || || || || || || || 1 1) 例如