property后面没有read和write是什么意思？

例如form的部分定义是这样的：
  TForm = class(TCustomForm)
  public
    procedure ArrangeIcons;
    procedure Cascade;
    procedure Next;
    procedure Previous;
    procedure Tile;
    property ActiveMDIChild;
    property ClientHandle;
    property DockManager;
    property MDIChildCount;
    property MDIChildren;
    property TileMode;
  ...请问怎么理解？？？