èç¹ï¼å¯¹äºä»»æç»å®çδ>0ï¼ç¹Pçå»å¿é¢åU(P,δï¼å
ï¼æ»æEä¸çç¹ï¼å称为Pæ¯Eçèç¹ãæ¤èç¹è¦ä¹æ¯å
ç¹ï¼è¦ä¹æ¯è¾¹çç¹ã
è±æï¼accumulation point
追é®è°¢è°¢ã
è¿ä¸ªè¯´æ³ï¼æ¯æ£è§çè±æåï¼
è±æä¸çaccumulation,accumulative,æ¯è¿æ ·ç¨çåï¼
æ£è§çè±ææä¹è§£éï¼
è½æä¾ä¸ä¸çè±æç½ååï¼