¡@1¢x2¢x3¡@ |
¡Dì¸ü©ó¬ì¾Ç¤ë¥Z²Ä¤K¨÷²Ä¥|´Á | ||
¼@Åܽ×(¤T)
½¹½ºÂI¼@ÅܤΨäÀ³¥Î ¿½ªY©¾ |
¦b«e½g¤¤§Ṳ́w¸gª¾¹D¨â±ÚºPÂI¼@ÅÜ (fold catastrophe) ·|¦X¦¨¤@Ó¦yÂI¼@ÅÜ (cusp catastrophe)¡A¦P¼Ë¨â±Ú¦yÂI¼@ÅÜ·|¦X¦¨¤@Ó¿P§ÀÂI¼@ÅÜ (swallowtail catastrophe)¡C¥»¤å·Q¨Ó¦Ò¼{¦p¦ó§â¨â±Ú¿P§ÀÂI¼@ÅÜ·|¦X¦¨¤@ӧ󰪤@¯Åªº½¹½ºÂI¼@ÅÜ (butterfly catastrophe)¡C
§Ų́ӦҼ{¨ã¦³¥|Ó°Ñ¼Æ (t,u,v,w) ªº¦h¶µ¦¡¡G
¨ä¾É¼Æ¬° V'(x)=x5+tx3+ux2+vx+w¡C¦b (t,u,v,w,x) ¤ºûªºªÅ¶¡¤¤¦Ò¼{¥ÑV'(x)=0©Ò¨M©wªº¥|ºû¶W¦±± (hypersurface) M¡A¥¦¥s°µ¼@Åܦ±Åé (catastrophe manifold)¡CM ®i¥¬¦b (t,u,v,w) ±±¨îªÅ¶¡¤§¤W¡C¥Ñ©óºû¼Æ¤Ó°ª¡A§ÚÌ·íµM¨S¿ìªk¥þ³¡µe¥X¨Ó¡C¦ý¬O§ÚÌ¥i¥H¥é³y«e½g¤§¤¤©Ò¨Ï¥Îªº¤èªk¡AÂÇµÛ V''(x)=5x4+3tx2+2ux+v¡A V'''(x)=20x3+6tx+2u ¥H¤Î V(4)(x)=60x2+6t ¨Ó§ä¥X¨º¨Ç¨Ï±o V'(x)=0 ¨ã¦³¤G«®Ú¡B¤T«®Ú©ÎªÌ¥|«®Ú¤§ÂI¡C§Ú̪¾¹D¡AY¤@ÂI (t,u,v,w) ¯à¦P®Éº¡¨¬¡GV'(x)=0 ¤Î V''(x)=0¡A«h V'(x)=0 ¨ã¦³¤G«®Ú¡C¦Ü©ó¯à°÷¦P®Éº¡¨¬ V'(x)=V''(x)=V'''(x)=0 ¤§±±¨îÂI (t,u,v,w)¡A·íµM´N¯à¨Ï V'(x)=0 ¨ã¦³¤T«®Ú¡C¦P¼ËÂǵ۸ÑÁp¥ß¤èµ{¦¡ V'(x)=V''(x)=V'''(x)=V(4)(x)=0 ¥i¥H±o¨ì©Ò¦³¨Ï±o V'(x)=0 ¨ã¦³¥|«®Ú¤§±±¨îÂI¡C³oÂI¶°¬O¤@±ø¦±½u¡A¨ä¤èµ{¦¡¬°¡G ¤j²¤»¡¨Ó¡A§Ú̪º¥Øªº¬O³o¼Ë¤lªº¡G§ÚÌ·Qn¦b±±¨îªÅ¶¡¤¤§ä¥X V'(x)=0 ªº§P§O¦¡ ( discriminant) K¡A³oÓ§P§O¦¡ K ¯à°÷§â¾ãÓ±±¨îªÅ¶¡ (t,u,v,w) ¤À¦¨Y¤z³¡¤À¡A¨Ï±o¦b¬Y¤@³¡¤À V'(x)=0 ³æ³æ¥u¦³¤@Ó¹ê®Ú¡A¦ý¬O¦b¥t¥~¤@³¡¤À V'(x)=0 «o¦³¤TÓ¹ê®Ú¡A¤S¦b§Oªº¤@³¡¤À V'(x)=0 ¨ã¦³¤Ó¹ê®Ú¡C¬JµM V(x) ¬OÓ¤»¦¸¤èµ{¦¡¡A·í x ¬°¥¿tµL½a¤j®É V(x) È¥²¬°¥¿µL½a¤j¡A¦Ó¥B V'(x)=0 ¤§¹ê®Ú¥Nªí y=V(x) ¦±½u¤§·¥¤j©Î·¥¤p¡A¥i¨£·í V'(x)=0 ¥u¦³¤@Ó¹ê®Ú®É¡A³o¹ê®Ú¥Nªí V(x) ªº·¥¤p¡C¦ýY V'(x)=0 ¦³¤TÓ¹ê®Ú¡A«h³o¤T®Ú«ö¤j¤p±Æ¦C¤À§O¬°·¥¤p¡B·¥¤j¡B·¥¤p¡C¦pªG V'(x)=0 ¦³¤Ó¹ê®Ú¡A«h«ö¤j¤p±Æ¦C¨Ì¦¸¬°·¥¤p¡B·¥¤j¡B·¥¤p¡B·¥¤j¡B·¥¤p¡C
¥Ñ(1)¦¡¡A¤@Ó±±¨îÂIY¨Ï±oV'(x)=0¨ã¦³¥|«®Ú¡A«htȤ£¥i¯à¬°¥¿È¡A¦]¦¹¬°¤F«K©óµe¥X§P§O¦¡Kªº¹Ï§Î¡A§Ų́ӦҼ{±±¨îªÅ¶¡¤¤ÀH«K¤@Ó¨ätȬ°±`¼Æªº¤TºûªÅ¶¡¡C§ÚÌ¥i¥H§â³o¨Çt=±`¼Æªº¤TºûªÅ¶¡°Ï¤À¬°¤TÃþ¡G
¬°¤F¤è«K°_¨£§Ṳ́À§O§â³o¤TÃþªº±±¨îªÅ¶¡¤¤ªº t ¬°±`¼Æªº¤TºûªÅ¶¡°O¬° Sa2, S0 ¥H¤Î S-a2¡Cº¥ý¨Ó¦Ò¼{ K ¦b Sa2 ¤¤ªººI±¡A¥¦À³¸Ó¬O Sa2 ¤¤ªº¤@Ó¦±±¡A¯à§â Sa2 µe¤À¦¨¤@¨Ç³¡¤À¡A¨Ï±o¦b¤£¦Pªº³¡¤À V'(x)=0 ¦³¤£¦P¼Æ¥Øªº¹ê®Ú¡C¹Ï¤@´Nµe¥X K ªº§Îª¬¡A¥¦¦n¹³¤@ӫγ»¥Ñ¨âÓ¦±±¡]¤G«®Ú¤§ÂI¡^ªuµÛ¦±½u C ¥æµ²¦Ó¦¨¡C¨ä¤¤ C ¬O Sa2 ¤¤¨Ï±o V'(x)=0 ¨ã¦³¤T«®Ú¤§ÂI©Ò¶°¦¨¡A¨ä¤èµ{¦¡¥i±q¸ÑÁp¥ß¤èµ{¦¡¡G V'(x)=V''(x)=V'''(x)=0 ¦Ó±o¡AÀ³¬°: u=-(10x3+3a2x), v=(15x4+3a2x2), w=-(6x5+a2x3)¡A³o¬O¤@±ø«Ü²³æªº¦±½u¡A¦p¹Ï¤@©Ò¥Ü¡C
¦b¤TºûªÅ¶¡ Sa2 ¤¤¦Ò¼{¦UÓ u=±`¼Æªº¥±¡A³oºØ¥±¸ò K ªº¥æ½u¤èµ{¦¡¥i¥HÂǵ۸Ñ
V'(x)=V''(x)=0¡]¨ä¤¤¥O t=a2¡Au= ±`¼Æ¡^¦Ó±o¡G
³oºØ¦±½uµe¥X¨Ó¤]¤Q¤À²³æ¡A¥u¬O¨Ç¦yÂI¦±½u¡A¨ä¦yÂI¸¨¦b¤T«®Ú¦±½u C ¤§¤W¡C¦]¦¹K¥iµø¬°¤@±Ú¨ä¦yÂIªuµÛCÅܰʪº¦yÂI¦±½u©Òºc¦¨ªº¦±±¡C³o¦±±§âSa2¹º¤À¦¨¨â³¡¤À¡A¦b¥~°¼ I ªº³¡¤À¡A¥u¦³¤@Ó¹ê®Ú¡A³o¬O¤@ÓV(x)ªº·¥¤p¡C¦ý¬O¦bKªº¤º°¼¡AV'(x)=0¦³¤TÓ¹ê®Ú¡A¬G¬°V(x)ªº¨âÓ·¥¤p§¨¤@Ó·¥¤j¡C¦]¦¹¦pªG·¥¤p¥Nªíéwªºª«²zª¬ºA¡A«h¦b II ¤¤¦s¦b¨âºØéwªºª«²zª¬ºA©¼¦¹¬ÛÄvª§¡C¦pªG±Ä¥ÎMaxwellªk«h¡A³W©w¦b¨ººØ¨Ï±o¨âÓ·¥¤p¨ã¦³¬Ûµ¥¤§VȤ§ÂI¡A³o¨âÓ·¥¤p©¼¦¹¬Û«ù¤£¤U¡A¤£¤À³Ót¡A§ÚÌ´N¥i¥H±o¨ì¤@Ó¥HC¬°Ãä¬Éªº¿E¾_ªi(shock wave)¦±±W¡A¥H¤À¹j³o¨âӬ۽Ĭð¬ÛÄvª§ªº·¥¤p¤§¶Õ¤O½d³ò¡C ¨ä¦¸¦Ò¼{K¦bS0¤¤ªººI±¡A¨ä±¡ªp¸ò¹Ï¤@§¹¥þÃþ¦ü¡A¥u¤£¹L³o®É¤T«®Ú¦±½uªº¤èµ{¦¡Åܬ°:u=-10x3,v=15x4,w=-6x5¡A³o¦±½u¦bìÂI¤Q¤Àªº¥ª½(flat)¡C¨CÓu=±`¼Æªº¥±»PKªº¥æ½u¤èµ{¦¡¬°:v=-(5x4+2ux),w=(4x5+ux2)¡C³o¤´µM³£¬O¦yÂI¦±½u¡C
K ¦b S-a2 ¤§¤¤ªººI±±¡§Î´NÅܱo¬Û·íªº½ÆÂø¡C¹Ï¤G¥ýµe¥X¤T«®Ú¦±½uC¡C³o®É¦±½u¤£¦A¹³¹Ï¤@¤¤ªºC¨º»ò³æ¯Â¡A¦]¬°¥¦ªº¤èµ{¦¡Åܦ¨¬°:
u=-(10x3-3a2x)
w=-(6x5-a2x3)
¨ä¤¤-3a2x,-3a2x2,-a2x3µ¥¶µ¦bxȤ£¤j®Éµo¥Í«Ü¤jªº§@¥Î¡A¨Ï±oC±q(-,+,-)ªº¶H(x¬°¤j¥¿È¤§®É)¤@ª½¦ù®i¨ìP1ÂI¡A¦b³o¨àC¦³¤@ÓÂà§é¡AµM«á¸g¹LìÂI¨ì¹FP2¡A¦b³o¨à²Ä¤G¦¸Âà§é¡A¦Ó³vº¥¦ù®i¦V(+,+,+)¶HªºµL½a»·³B¡C³o¨âÓ¯S§OªºÂà§éÂI¨ä¹ê¥¿¬O¥|«®ÚÂI¡C°O±o(1)¦¡¦b±±¨îªÅ¶¡¤¤¬°¤@±ø¦±½u¡A¥¦¸òS-a2ªº¥æÂI´N¬O¦b(1)¦¡¤¤¥Ot=-10x2=-a2¡A¦]¦¹ ¦Ó¦³ ¡A³o¼ËªºxȤÀ§O¥N¤Ju,v,w«K±oP1,P2¨âÂI¡C¦±½uC¥Ñ©óÂà¤F¨â§é¡A¦b¹Ï¤G¤¤§Îª¬¹³¿P§À§Î¡A¦ý¬On°O±oC¨Ã¤£¸ò¥»¨¬Û¥æ¡C·íu=0®É¡A¥Ñ(2)¦¡ ¡A¦]¦¹ ¡Aªí¥Ü¥Ñ(-,+,-)¤É¤W¨Ó²Ä¤@¦¸¸I¨ìu=0¥±¤§®ÉwȬ°t¡A¦ý¦±½u¨ìP1®ÉwȤw¤É¬° ¡AÂà§é«áwȳvº¥´î¤Ö¨ì0¦A´î¤Ö¨ìP2¤§ ¡A¦bP2Âà§é«áwÈ«æ³t¤W¤É¡Aµ¥¨ì¦±½u¦b¥æu=0ªº¥±®Éw¤S¤w¸g¬O¥¿È ¤F¡C
²{¦b§ÚÌnÂǵ۹ϤT¨Ó¬Ý¥XS-a2ùØKªº§Îª¬¨ì©³¦p¦ó¡CÁÙ¬O·Ó¼Ë¨ú¦UÓu=±`¼Æªº¥±¡A³oºØ¥±¸òKªº¥æ½u¤èµ{¦¡¬O:
·íu=±`¼Æ¤p©ó ©Î¤j©ó ®É¡A(3)¦¡§Îª¬«Ü¦n¡A³£¬O¦yÂI¦±½u¡A´N¹³¹Ï¤T¤¤³Ì¥ªÃä©Î³Ì¥kÃ䪺¥æ½u¡C¦ý¬O·íu=±`¼Æ¥ÑP2ªº ÅܤƨìP1ªº ®É¡A³o¥æ½uªº§Îª¬Åܱo¤j¬°¤£¦P¡C±q¶}©l¥X²{¤@Ó¤p¤pªº¿P§À§Î¡AºtÅܦ¨³oÓ¤p¿P§À§Î¨ë¹L¦yÂI¦±½uªº¥t¤@¤ä¦Óµ²ªG§Î¦¨¨âÓÁp¦X¦b¤@°_¦@¦³¤@Ó¦@¦P¦yÂIªº¿P§À§Î¡CµM«á¤@Ó¿P§À§Î¦¬ÁY¡A¤SºtÅܦ¨³æ³æ³Ñ¤U¤@Ó¤p¿P§À§Î¡A¦Ó«á³vº¥§¹¥þ®ø¥¢¡C
·íu=¤pȪº±`¼Æ®É¡A(3)¦¡³o±ø¦±½uªº§Îª¬«Ü¹³½¹½º¡F¥un§â¹Ï¤T¤W¤èªº²Ä¥|ºI±¹ÏÄA˹L¨Ó¬Ý´N¬O¡C³o¦±½u§âu=±`¼Æªº¥±¹º¤À¬°´X³¡¤À¡GIªº³¡¤À¥u¦³¤@Ó¹ê®Ú¡A¦]¦¹V(x)¥u¦³¤@Ó·¥¤p¡CIIIªº³¡¤À¦³¤Ó¹ê®Ú¡A¦]¦¹¦³¤TÓ·¥¤p¡C¨âÓ³QÂI¤F¤@¤pÂIªº¤T¨¤§Î¥H¤ÎIIªº³¡¤À¦³¤TÓ¹ê®Ú¡A¦]¦¹¦³¨âÓ·¥¤p¡C¦b¹Ï¥|¤¤§Ú̯à§â³o¥ó¨Æ¬Ý±o§ó¥[²M·¡¡C¦bV'(x)=0¡A¥Ot=-a2¡Au=±`¼Æ¡A«h V'(x)=x5-a2x3+ux2+vx+w=0Åܦ¨¤@Ó®i¥¬©ó(v,w)¥±¤Wªº¦±±¡A¦bI¤W¥u¦³¤@¼h¡]¤@Ó·¥¤p¡^¡A¦ý¬O¦bIIªº³¡¤À½T¦³¤T¼h¡]¤GÓ·¥¤p¡B¤@Ó·¥¤j¡^¡A¦bIIIªº³¡¤À¦³¤¼h¡]¤TÓ·¥¤p¡B¤GÓ·¥¤j¡^¡C³oÓ¦±±´N¬O¼@Åܦ±ÅéM¦b Su-a2 x x-¶b³oÓ¤TºûªÅ¶¡ùØ©Ò§e²{ªº¼Ë¤l¡A¨ä¤¤Su-a2¥NªíS-a2¤§¤¤u=±`¼Æªº¥±¡C
¹Ï¥|¤¤·íu¬OÓ¤£¬°0ªº¤pȱ`¼Æ®É¡ASu-a2¥±¤¤ªº½¹½º§Î¦±½u¹ï©óv¶b¨Ã¤£¹ïºÙ¡A½¹½º§Î¬O°¾¦V§á¦±ªº¡C¦ý¬O¦pªGu=0¡A«h(3)¦¡Åܬ° v=-(5x4-3a2x2)¡A w=4x5-2a2x3¡C³o¬OÓ¹ï©óv¶b¹ïºÙªº¥¿½¹½º§Î¡C¥Ñ©óuȪºÅܤƷ|¼vÅT½¹½º¦±½uªº§Îª¬¡A¦]¦¹u³q±`´N¥s°µ°¾¦V¦]¤l(bias factor)¡C¦b¹Ï¥|¤¤¦pªG§Ú̦Ҽ{v=±`¼Æªº¥±°µ¬°ºI±¸òM©Ò§Î¦¨ªº¥æ½u¡A§Ú̯à¬Ý¥X¡A·ív=tȱ`¼Æ®É(¦Ò¼{ª½½uE1)¡A³o¥æ½uªº§Îª¬§Ṳ́Q¤À¼ô±x¡A¥¦¨ä¹ê¤w¥X²{¦b¦yÂI¼@Åܪº¼Ò«¬¤§¤¤¡A¤W¤U¨â¤ä¥Nªí·¥¤p¡A¤¤¬q«o¥Nªí·¥¤j¡C¦]¦¹¹ï©óv¤p©ó0¦Ó¨¥¡A¹Ï¥|¨ä¹ê´N¬OÓ¦yÂI¼@Åܪº¼Ò«¬¡C±±¨î¦]¤lªuµÛE1ÅÜ°Ê·|²£¥Í¬ðµMªº¤£³sÄòªº¼@Åܲ{¶H¡A¥Ñ¤@Ó·¥¤p¸õ¨ì¥t¤@Ó·¥¤p¡C¦p¦P«e½g¤¤¤w©w¸q¡A§Ú̺Ùv¬°¤Àµõ¦]¤l(splitting factor)¡AºÙw¬°¥¿«h¦]¤l(normal factor)¡C¥t¤@¤è±¡A¦b¹Ï¥|¤¤¡A·ív¬OÓ¤ñ¸û¤jªº¥¿È±`¼Æ®É¡A¨Ò¦p¦Ò¼{E2ª½½u(·íu=0®É¡A¥Ñ(3)¦¡®e©öºâ¥X¥u»Ýn¨Dv¤j©ó «K¥i)¡A³o¥æ½u®Ú¥»¤£¥´ºP¡A¦]¦¹±±¨î¦]¤lªuµÛE2Åܰʮɮڥ»¤£²£¥Í¥ô¦ó¼@Åܲ{¶H¡A³o¤]¬O¦yÂI¼@Åܼҫ¬¤¤§ÚÌ©Ò¦¤w¼ô±x¤Fªº¡C¹Ï¥|³oÓ¼Ò«¬¤¤³Ì¦³½ìªº³¡¤À¬O·ívµ¥©ó¤pȪº¥¿¼Æ¤§®É¡A¦]¦¹Åý§Ú̦Ҽ{Su-a2¤¤¥¦æ©ów¶bªºª½½uE3¤ÎE4¡A³o®ÉM¤W¦ì©óE3¤ÎE4¤W¤èªº¨â±ø¦±½u§Îª¬¤À§Oµe¦¨¹Ï¤ ¤§¤¤ªºE'3¤ÎE'4¡C³o¨â±ø¦±½u³£¥´¤F¥|ºP¡A¤W¤U¤Î¤¤¶¡ªº¹ê½u¬q¥Nªí·¥¤p¡A³sµ²³o¨Ç¹ê½u¬qªºÂI½u¬q¥Nªí·¥¤j¡C
¦bE'4 ªº±¡§Î¡A¦pªG±±¨îÂIªuµÛE4±q¥k©¹¥ª²¾°Ê¡A¦Ó¥B§Ų́ϥβĤG½g©Ò¤¶²Ðªº©ì©µªk«h(Delay Rule)¡A«h·¥¤p³Ìªì¦ì©óE'4ªº³Ì¤W¤ä¡A¤@ª½³sÄò²¾°Ê¨ìAÂI¡AµM«áµo¥Í¼@Åܲ{¶H¤@¤U¤l±qA¸õÅD¨ì¤¤¼hªºA'ÂI¡AµM«á³sÄòªu¤¤¼h¤@ª½¨«¨ìA''¡A¦A¦¸µo¥Í¼@ÅܦӸõÅD¨ì³Ì©³¤Uªº·¥¤pA'''¡C¤Ï¹L¨Ó¡A¦pªG±±¨îÂI¬O¦bE4¤W±q¥ª©¹¥k²¾°Ê¡A«h·¥¤p¦b³Ì¤U¤ä¥k²¾¨ìBÂI¡Aµo¥Í¼@Åܸõ¨ì¤¤¤äªºB'ÂI¡AµM«á³sÄòªu¤¤¤ä¥k²¾¨ìB''ÂI¦A¦¸µo¥Í¼@ÅܦӸõ¨ì¤W¤äªºB'''ÂI¡C¦ý¬O¦pªG¦Ò¼{E'3½u¡A±¡§Î´N¦³ÂI¤£¦P¡A³o®É¾¨ºÞ¤´¦³¤¤¶¡ªº·¥¤p¦s¦b¡A¦ý¬O¥¦ªº½d³ò¤£«Ü¤j¡A¨Ã¤£¦ì©óA(©ÎB)ÂIªº¤U(©Î¤W)¤è¡A¦]¦¹Y¨Ï¥Î©ì©µªk«h«h¼@Åܲ{¶Hª½±µ¦b¤W¤U¤ä¤§¶¡Åܨì¡A¤£¨ú¹D¤¤¤äªº·¥¤p¡C
|
¹ï¥~·j´MÃöÁä¦r¡G ¡DMaxwell ¡Dtransversality |
|
¡]Y¦³«ü¥¿¡BºÃ°Ý¡K¡K¡A¥i¥H¦b¦¹ ¯d¨¥ ©Î ¼g«H µ¹§ÚÌ¡C¡^ |
EpisteMath (c) 2000 ¤¤¥¡¬ã¨s°|¼Æ¾Ç©Ò¡B¥x¤j¼Æ¾Ç¨t ¦Uºô¶¤å³¹¤º®e¤§µÛ§@Åv¬°ìµÛ§@¤H©Ò¦³ |
½s¿è¡G³¯¤å¬O | ³Ì«áקï¤é´Á¡G5/2/2002 |