Do declared properties require a corresponding instance variable?

Do properties in Objective-C 2.0 require a corresponding instance variable to be declared? For example, I'm used to doing something like this:

MyObject.h

@interface MyObject : NSObject {
NSString *name;
}
@property (nonatomic, retain) NSString *name;
@end

MyObject.m

@implementation
@synthesize name;
@end

However, what if I did this instead:

MyObject.h

@interface MyObject : NSObject {
}
@property (nonatomic, retain) NSString *name;
@end

Is this still valid? And is it in any way different to my previous example?