Е. Деза_ М.М. Деза. Энциклопедический словарь расстояний (2008) (1185330), страница 38
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éÒË ÍÓÌÛÒ‡ ë – n ÎÛ˜ÂÈ, „‰Â ͇ʉ˚È ÎÛ˜ ËÒıÓ‰ËÚ ËÁ ̇˜‡Î‡ ÍÓÓ‰ËÌ‡Ú Ë ÒÓ‰ÂÊËÚ Ó‰ÌÛ ËÁ ÚÓ˜ÂÍ ÏÌÓÊÂÒÚ‚‡ ï.164ó‡ÒÚ¸ II. ÉÂÓÏÂÚËfl ‡ÒÒÚÓflÌËflÑÎfl ‡Á·ËÂÌËfl {C1,..., Ck} ÔÓÒÚ‡ÌÒÚ‚‡ n ̇ ÏÌÓÊÂÒÚ‚Ó ÒËÏÔÎˈˇθÌ˚ı ÍÓÌÛÒÓ‚ C 1 ,..., Ck k-ÓËÂÌÚËÓ‚‡ÌÌ˚Ï ‡ÒÒÚÓflÌËÂÏ Ì‡Á˚‚‡ÂÚÒfl ÏÂÚË͇ ̇ n, Á‡‰‡Ì̇fl ͇Ídk(x – y)‰Îfl ‚ÒÂı x, y ∈ n, „‰Â ‰Îfl β·Ó„Ó x ∈ Ci Á̇˜ÂÌË dk(x) ÂÒÚ¸ ‰ÎË̇ ̇Ë͇ژ‡È¯Â„ÓÔÛÚË ÓÚ Ì‡˜‡Î‡ ÍÓÓ‰ËÌ‡Ú ‰Ó ÚÓ˜ÍË ı ÔË ÔÂÂÏ¢ÂÌËË ÚÓθÍÓ ÔÓ Ì‡Ô‡‚ÎÂÌËflÏ,Ô‡‡ÎÎÂθÌ˚Ï ÓÒflÏ ÍÓÌÛÒ‡ ë.åÂÚËÍË ÍÓÌÛÒ‡äÓÌÛÒÓÏ Con(X, d) ̇‰ ÏÂÚ˘ÂÒÍËÏ ÔÓÒÚ‡ÌÒÚ‚ÓÏ (X, d) ̇Á˚‚‡ÂÚÒfl Ù‡ÍÚÓÔÓËÁ‚‰ÂÌË X × ≥0 , ÔÓÎÛ˜ÂÌÌÓ ÓÚÓʉÂÒÚ‚ÎÂÌËÂÏ ‚ÒÂı ÚÓ˜ÂÍ ÌËÚË X × {0}.íӘ͇, ÒÓÓÚ‚ÂÚÒÚ‚Û˛˘‡fl ÏÌÓÊÂÒÚ‚Û X × {0}, ̇Á˚‚‡ÂÚÒfl ‚¯ËÌÓÈ ÍÓÌÛÒ‡.åÂÚË͇ ‚ÍÎˉӂ‡ ÍÓÌÛÒ‡ – ÏÂÚË͇ ̇ Con(X), Á‡‰‡Ì̇fl ‰Îfl β·˚ı (x, y),(y, s) ∈ Con(X, d) ͇Ít 2 + s 2 − 2ts cos(min{d ( x, y), π}).äÓÌÛÒ Con(X, d) Ò ˝ÚÓÈ ÏÂÚËÍÓÈ Ì‡Á˚‚‡ÂÚÒfl ‚ÍÎˉӂ˚Ï ÍÓÌÛÒÓÏ Ì‡‰ ÏÂÚ˘ÂÒÍËÏ ÔÓÒÚ‡ÌÒÚ‚ÓÏ (X, d).ÖÒÎË (X, d) – ÍÓÏÔ‡ÍÚÌÓ ÏÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Ó ‰Ë‡ÏÂÚ‡ <2, ÚÓ ÏÂÚËÍÓÈä‡ÍÛÒ‡ ̇Á˚‚‡ÂÚÒfl ÏÂÚË͇ ̇ Con(X, d), ÓÔ‰ÂÎflÂχfl ‰Îfl β·˚ı (x, y) ,(y, s) ∈ Con(X, d) ͇Ímin{s, t}d(x, y) + | t – s |.äÓÌÛÒ Con(X, d) Ò ÏÂÚËÍÓÈ ä‡ÍÛÒ‡ ‰ÓÔÛÒ͇ÂÚ ÒÛ˘ÂÒÚ‚Ó‚‡ÌË ‰ËÌÒÚ‚ÂÌÌÓÈÒ‰ËÌÌÓÈ ÚÓ˜ÍË ‰Îfl ͇ʉÓÈ Ô‡˚ Â„Ó ÚÓ˜ÂÍ, ÂÒÎË (X, d) ӷ·‰‡ÂÚ Ú‡ÍËÏ Ò‚ÓÈÒÚ‚ÓÏ.ÖÒÎË M n fl‚ÎflÂÚcfl ÏÌÓ„ÓÓ·‡ÁËÂÏ Ò (ÔÒ‚‰Ó)ËχÌÓ‚ÓÈ ÏÂÚËÍÓÈ g, ÚÓ ÏÓÊÌÓ1‡ÒÒχÚË‚‡Ú¸ ÏÂÚËÍÛ dr2 + r 2 g (‚ Ó·˘ÂÏ ÒÎÛ˜‡Â ÏÂÚËÍÛ dr 2 + r 2 g, k ≠ 0) ̇kCon(Mn ) = Mn × >0.åÂÚË͇ ‚Á‚ÂÒËëÙ¢ÂÒÍËÈ ÍÓÌÛÒ (ËÎË ‚Á‚ÂÒ¸) Σ(X) ̇‰ ÏÂÚ˘ÂÒÍËÏ ÔÓÒÚ‡ÌÒÚ‚ÓÏ (X, d) ÂÒÚ¸Ù‡ÍÚÓ-ÔÓËÁ‚‰ÂÌË X × [0, a], ÔÓÎÛ˜ÂÌÌÓ ÓÚÓʉÂÒÚ‚ÎÂÌËÂÏ ‚ÒÂı ÚÓ˜ÂÍ ÌËÚÂÈX × {0} Ë X × {a}.ÖÒÎË (X, d) fl‚ÎflÂÚÒfl ÔÓÒÚ‡ÌÒÚ‚ÓÏ ‰ÎËÌ˚ c ‰Ë‡ÏÂÚÓÏ diam(X) ≤ π Ë a = π, ÚÓÏÂÚËÍÓÈ ‚Á‚ÂÒË Ì‡Á˚‚‡ÂÚÒfl ÏÂÚË͇ ̇ Σ(X), Á‡‰‡Ì̇fl ‰Îfl β·˚ı (x, y), y, s) ∈ Σ(X)͇Íarccos(costcoss + sintsinscosd(x, y)).9.3.
êÄëëíéüçàü çÄ ëàåèãàñàÄãúçõï äéåèãÖäëÄïr-åÂÌ˚È ÒËÏÔÎÂÍÒ (ËÎË „ÂÓÏÂÚ˘ÂÒÍËÈ ÒËÏÔÎÂÍÒ, „ËÔÂÚÂÚ‡˝‰) Ô‰ÒÚ‡‚ÎflÂÚÒÓ·ÓÈ ‚˚ÔÛÍÎÛ˛ Ó·ÓÎÓ˜ÍÛ r + 1 ÚÓ˜ÂÍ ËÁ n, ÍÓÚÓ˚ Ì ÔË̇‰ÎÂÊ‡Ú ÌË͇ÍÓÈ(r – 1)-ÔÎÓÒÍÓÒÚË. ëËÏÔÎÂÍÒ ÔÓÎÛ˜ËÎ Ò‚Ó ̇Á‚‡ÌË ÔÓÚÓÏÛ, ˜ÚÓ Ó·ÓÁ̇˜‡ÂÚ ÔÓÒÚÂȯËÈ ‚ÓÁÏÓÊÌ˚È ‚˚ÔÛÍÎ˚È ÏÌÓ„Ó„‡ÌÌËÍ ‚ β·ÓÏ Á‡‰‡ÌÌÓÏ ÔÓÒÚ‡ÌÒÚ‚Â.r (r + 1)ɇÌˈ‡ r-ÒËÏÔÎÂÍÒ‡ ËÏÂÂÚ r + 1 0-„‡ÌÂÈ (‚¯ËÌ ÏÌÓ„Ó„‡ÌÌË͇),12165É·‚‡ 9. ê‡ÒÒÚÓflÌËfl ̇ ‚˚ÔÛÍÎ˚ı Ú·ı, ÍÓÌÛÒ‡ı Ë ÒËÏÔÎˈˇθÌ˚ı ÍÓÏÔÎÂÍÒ‡ı r + 1 r„‡ÌÂÈ (· ÏÌÓ„Ó„‡ÌÌË͇) Ë i-„‡ÌÂÈ, „‰Â – ·ËÌÓÏˇθÌ˚È ÍÓ˝Ù i + 1 iÙˈËÂÌÚ. ÇÏÂÒÚËÏÓÒÚ¸ (Ú.Â.
ÏÌÓ„ÓÏÂÌ˚È Ó·˙eÏ) ÒËÏÔÎÂÍÒ‡ ÏÓÊÂÚ ·˚Ú¸ ‚˚˜ËÒÎÂ̇ Ò ÔÓÏÓ˘¸˛ ÓÔ‰ÂÎËÚÂÎfl ä˝ÎË–åÂ̄‡. 臂ËθÌ˚È r-ÏÂÌ˚È ÒËÏÔÎÂÍÒÓ·ÓÁ̇˜‡ÂÚÒfl Í‡Í αr.ÉÛ·Ó „Ó‚Ófl, „ÂÓÏÂÚ˘ÂÒÍËÈ ÒËÏÔÎˈˇθÌ˚È ÍÓÏÔÎÂÍÒ – ÔÓÒÚ‡ÌÒÚ‚Ó ÒÚˇ̄ÛÎflˆËÂÈ, Ú.Â. ‡Á·ËÂÌËÂÏ Â„Ó Ì‡ Á‡ÏÍÌÛÚ˚ ÒËÏÔÎÂÍÒ˚ Ú‡ÍËÏ Ó·‡ÁÓÏ, ˜ÚÓβ·˚ ‰‚‡ ÒËÏÔÎÂÍÒ‡ ÎË·Ó ‚ÓÓ·˘Â Ì ÔÂÂÒÂ͇˛ÚÒfl, ÎË·Ó ÔÂÂÒÂ͇˛ÚÒfl ÔÓ Ó·˘ÂÈ„‡ÌË.Ä·ÒÚ‡ÍÚÌ˚È ÒËÏÔÎˈˇθÌ˚È ÍÓÏÔÎÂÍÒ S – ÏÌÓÊÂÒÚ‚Ó Ò ˝ÎÂÏÂÌÚ‡ÏË, ̇Á˚‚‡ÂÏ˚ÏË ‚¯Ë̇ÏË, ‚ ÍÓÚÓ˚ı ‚˚‰ÂÎÂÌÓ ÒÂÏÂÈÒÚ‚Ó ÌÂÔÛÒÚ˚ı ÔÓ‰ÏÌÓÊÂÒÚ‚, ̇Á˚‚‡ÂÏ˚ı ÒËÏÔÎÂÍÒ‡ÏË, Ú‡ÍËÏ Ó·‡ÁÓÏ, ˜ÚÓ Í‡Ê‰Ó ÌÂÔÛÒÚÓ ÔÓ‰ÏÌÓÊÂÒÚ‚Ó ÒËÏÔÎÂÍÒ‡ s fl‚ÎflÂÚÒfl ÒËÏÔÎÂÍÒÓÏ, ̇Á˚‚‡ÂÏ˚Ï „‡Ì¸˛ s, Ë Í‡Ê‰Ó ӉÌÓ˝ÎÂÏÂÌÚÌÓÂÔÓ‰ÏÌÓÊÂÒÚ‚Ó fl‚ÎflÂÚÒfl ÒËÏÔÎÂÍÒÓÏ.
ëËÏÔÎÂÍÒ Ì‡Á˚‚‡ÂÚÒfl i-ÏÂÌ˚Ï, ÂÒÎË ÒÓÒÚÓËÚËÁ i + 1 ‚¯ËÌ. ê‡ÁÏÂÌÓÒÚ¸˛ S fl‚ÎflÂÚÒfl χÍÒËχθ̇fl ‡ÁÏÂÌÓÒÚ¸ Â„Ó ÒËÏÔÎÂÍÒÓ‚. ÑÎfl Í‡Ê‰Ó„Ó ÒËÏÔÎˈˇθÌÓ„Ó ÍÓÏÔÎÂÍÒ‡ S ÒÛ˘ÂÒÚ‚ÛÂÚ Úˇ̄ÛÎflˆËfl ÏÌÓ„Ó„‡ÌÌË͇, ‰Îfl ÍÓÚÓÓÈ S fl‚ÎflÂÚÒfl ÒËÏÔÎˈˇθÌ˚Ï ÍÓÏÔÎÂÍÒÓÏ. í‡ÍÓÈ „ÂÓÏÂÚ˘ÂÒÍËÈ ÒËÏÔÎˈˇθÌ˚È ÍÓÏÔÎÂÍÒ Ó·ÓÁ̇˜‡ÂÚÒfl GS Ë Ì‡Á˚‚‡ÂÚÒfl „ÂÓÏÂÚ˘ÂÒÍÓÈ Â‡ÎËÁ‡ˆËÂÈ S.ëËÏÔÎˈˇθ̇fl ÏÂÚË͇èÛÒÚ¸ S – ‡·ÒÚ‡ÍÚÌ˚È ÒËÏÔÎˈˇθÌ˚È ÍÓÏÔÎÂÍÒ Ë GS – „ÂÓÏÂÚ˘ÂÒÍËÈ ÒËÏÔÎˈˇθÌ˚È ÍÓÏÔÎÂÍÒ, fl‚Îfl˛˘ËÈÒfl „ÂÓÏÂÚ˘ÂÒÍÓÈ Â‡ÎËÁ‡ˆËÂÈ S. íÓ˜ÍË GSÏÓÊÌÓ ÓÚÓʉÂÒÚ‚ËÚ¸ Ò ÙÛÌ͈ËflÏË α: S → [0, 1], ‰Îfl ÍÓÚÓ˚ı ÏÌÓÊÂÒÚ‚Ó{x ∈ S: α(x) ≠ 0} fl‚ÎflÂÚÒfl ÒËÏÔÎÂÍÒÓÏ ‚ S Ëα( x ) = 1.
óËÒÎÓ α(x) ̇Á˚‚‡ÂÚÒfl ı-È∑x ∈S·‡ËˆÂÌÚ˘ÂÒÍÓÈ ÍÓÓ‰Ë̇ÚÓÈ α.ëËÏÔÎˈˇθ̇fl ÏÂÚË͇ – ÏÂÚË͇, Á‡‰‡Ì̇fl ̇ GS ͇Í∑(α( x ) − β( x ))2 .x ∈SåÌÓ„Ó„‡Ì̇fl ÏÂÚË͇åÌÓ„Ó„‡ÌÌÓÈ ÏÂÚËÍÓÈ Ì‡Á˚‚‡ÂÚÒfl ‚ÌÛÚÂÌÌflfl ÏÂÚË͇ Ò‚flÁÌÓ„Ó „ÂÓÏÂÚ˘ÂÒÍÓ„Ó ÒËÏÔÎˈˇθÌÓ„Ó ÍÓÏÔÎÂÍÒ‡ ‚ n, ‚ ÍÓÚÓÓÏ ÓÚÓʉÂÒÚ‚ÎÂÌÌ˚ „‡Ìˈ˚ËÁÓÏÂÚ˘Ì˚ àÏÂÌÌÓ, Ó̇ ÓÔ‰ÂÎflÂÚÒfl Í‡Í ËÌÙËÏÛÏ ‰ÎËÌ ‚ÒÂı ÎÓχÌ˚ı ÎËÌËÈ,ÒÓ‰ËÌfl˛˘Ëı ÚÓ˜ÍË ı Ë Û Ú‡Í, ˜ÚÓ Í‡Ê‰Ó ËÁ Á‚Â̸‚ ÔË̇‰ÎÂÊËÚ Ó‰ÌÓÏÛ ËÁÒËÏÔÎÂÍÒÓ‚.èËÏÂÓÏ ÏÌÓ„Ó„‡ÌÌÓÈ ÏÂÚËÍË fl‚ÎflÂÚÒfl ‚ÌÛÚÂÌÌflfl ÏÂÚË͇ ̇ ÔÓ‚ÂıÌÓÒÚËÏÌÓ„Ó„‡ÌÌË͇ ‚ n .
åÌÓ„Ó„‡ÌÌÛ˛ ÏÂÚËÍÛ ÏÓÊÌÓ ‡ÒÒχÚË‚‡Ú¸ ̇ ÍÓÏÔÎÂÍÒÂÒËÏÔÎÂÍÒÓ‚ ‚ ÔÓÒÚ‡ÌÒÚ‚Â ÔÓÒÚÓflÌÌÓÈ ÍË‚ËÁÌ˚. Ç Ó·˘ÂÏ ÒÎÛ˜‡Â ÏÌÓ„Ó„‡ÌÌ˚ÂÏÂÚËÍË ‡ÒÒχÚË‚‡˛ÚÒfl ‰Îfl ÍÓÏÔÎÂÍÒÓ‚, fl‚Îfl˛˘ËıÒfl ÏÌÓ„ÓÓ·‡ÁËflÏË ËÎË ÏÌÓ„ÓÓ·‡ÁËflÏË Ò Í‡ÂÏ.åÂÚË͇ ÔÓÎË˝‰‡Î¸Ì˚ı ˆÂÔÂÈmr-åÂ̇fl ÔÓÎË˝‰‡Î¸Ì‡fl ˆÂÔ¸ Ä ‚ n Á‡‰‡ÂÚÒfl ÎËÌÂÈÌ˚Ï ‚˚‡ÊÂÌËÂÏ∑ ditir ,i =1„‰Â ‰Îfl β·Ó„Ó i ‚Â΢Ë̇ tir fl‚ÎflÂÚÒfl r-ÏÂÌ˚Ï ÒËÏÔÎÂÍÒÓÏ ‚ n .
ɇÌˈÂÈ ˆÂÔË166ó‡ÒÚ¸ II. ÉÂÓÏÂÚËfl ‡ÒÒÚÓflÌËflfl‚ÎflÂÚÒfl ÎËÌÂÈ̇fl ÍÓÏ·Ë̇ˆËfl „‡Ìˈ ÒËÏÔÎÂÍÒÓ‚ ˆÂÔË. ɇÌˈÂÈ r-ÏÂÌÓÈ ÔÓÎË˝‰‡Î¸ÌÓÈ ˆÂÔË fl‚ÎflÂÚÒfl (r – 1)-ÏÂ̇fl ˆÂÔ¸.åÂÚËÍÓÈ ÔÓÎË˝‰‡Î¸Ì˚ı ˆÂÔÂÈ fl‚ÎflÂÚÒfl ÏÂÚË͇ ÌÓÏ˚|| A – B ||̇ ÏÌÓÊÂÒÚ‚Â Cr( n ) ‚ÒÂı r-ÏÂÌ˚ı ÔÓÎË˝‰‡Î¸Ì˚ı ˆÂÔÂÈ.
Ç Í‡˜ÂÒÚ‚Â ÌÓÏ˚ ̇C r( n ) ÏÓÊÂÚ ·˚Ú¸ ÔËÌflÚ‡.m1. å‡ÒÒ‡ ÔÓÎË˝‰‡Î¸ÌÓÈ ˆÂÔË, Ú.Â. | A |=∑| di | | tir |, „‰Â | t r | – Ó·˙ÂÏ Á‚Â̇ tir .i =12. ÅÂÏÓθ̇fl ÌÓχ ÔÓÎË˝‰‡Î¸ÌÓÈ ˆÂÔË, Ú.Â. | A |b = inf D {| A − ∂D | + | D |}, „‰Â| D | – χÒÒ‡ D , ∂D – „‡Ìˈ‡ D Ë ËÌÙËÏÛÏ ·ÂÂÚÒfl ÔÓ ‚ÒÂÏ (r + 1)-ÏÂÌ˚ÏÔÓÎË˝‰‡Î¸Ì˚Ï ˆÂÔflÏ; ÔÓÔÓÎÌÂÌË ÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ (Crb (n ), | ⋅ |b ) ·ÂÏÓθÌÓÈ ÌÓÏÓÈ fl‚ÎflÂÚÒfl ÒÂÔ‡‡·ÂθÌ˚Ï ·‡Ì‡ıÓ‚˚Ï ÔÓÒÚ‡ÌÒÚ‚ÓÏ, Ó·ÓÁ̇˜‡ÂÏ˚Ï Í‡Í Crb (n ), Â„Ó ˝ÎÂÏÂÌÚ˚ ËÁ‚ÂÒÚÌ˚ Í‡Í r-ÏÂÌ˚ ·ÂÏÓθÌ˚ ÔÎÓÒÍË ˆÂÔË.3. ÑËÂÁ̇fl ÌÓχ ÔÓÎË˝‰‡Î¸ÌÓÈ ˆÂÔË, Ú.Â.b| A | = inf m∑i =1| di | | tir | | vi |r +1m+∑ di Tv tiri =1ib,„‰Â | A | b – ·ÂÏÓθ̇fl ÌÓχ Ä Ë ËÌÙËÏÛÏ ·ÂÂÚÒfl ÔÓ ‚ÒÂÏ Ò‰‚Ë„‡Ï v (Á‰ÂÒ¸ Tytr –Á‚ÂÌÓ, ÔÓÎÛ˜ÂÌÌÓ ÔÂÂÏ¢ÂÌËÂÏ tr ̇ ‚ÂÍÚÓ v ‰ÎËÌ˚ | v |); ÔÓÔÓÎÌÂÌË ÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ (Cr (n ),| ⋅ | # ) ‰ËÂÁÌÓÈ ÌÓÏÓÈ fl‚ÎflÂÚÒfl ÒÂÔ‡‡·ÂθÌ˚Ï ·‡Ì‡ıÓ‚˚Ï ÔÓÒÚ‡ÌÒÚ‚ÓÏ, Ó·ÓÁ̇˜‡ÂÏ˚Ï Í‡Í Cr# (n ), Â„Ó ˝ÎÂÏÂÌÚ˚ ̇Á˚‚‡˛ÚÒflr-ÏÂÌ˚ÏË ‰ËÂÁÌ˚ÏË ÔÎÓÒÍËÏË ˆÂÔflÏË.
ÅÂÏÓθ̇fl ˆÂÔ¸ ÍÓ̘ÌÓÈ Ï‡ÒÒ˚ fl‚ÎflÂÚÒfl‰ËÂÁÌÓÈ. ÖÒÎË r = 0, ÚÓ | A |b =| A | # .åÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Ó ÔÓÎË˝‰‡Î¸Ì˚ı ÍÓˆÂÔÂÈ (Ú.Â. ÎËÌÂÈÌ˚ı ÙÛÌ͈ËÈÔÓÎË˝‰‡Î¸Ì˚ı ˆÂÔÂÈ) ÏÓÊÂÚ ·˚Ú¸ Á‡‰‡ÌÓ ‡Ì‡Îӄ˘Ì˚Ï ÒÔÓÒÓ·ÓÏ. Ç Í‡˜ÂÒÚ‚ÂÌÓÏ˚ ÔÓÎË˝‰‡Î¸ÌÓÈ ÍÓˆÂÔË ï ÏÓÊÂÚ ·˚Ú¸ ÔËÌflÚ‡:1. äÓχÒÒ‡ ÔÓÎË˝‰‡Î¸ÌÓÈ ÍÓˆÂÔË, Ú.Â. | X(A) , „‰Â ï(Ä) – Á̇˜ÂÌË ÍÓˆÂÔË ï ̇ˆÂÔË Ä.2. ÅÂÏÓθ̇fl ÍÓÌÓχ ÔÓÎË˝‰‡Î¸ÌÓÈ ÍÓˆÂÔË, Ú.Â.
| X |b = sup| A| b =1{X ( A) | .3. ÑËÂÁ̇fl ÍÓÌÓχ ÔÓÎË˝‰‡Î¸ÌÓÈ ÍÓˆÂÔË, Ú.Â. | X | # = sup| A| # =1 | X ( A) | .ó‡ÒÚ¸ IIIêÄëëíéüçàüÇ äãÄëëàóÖëäéâ åÄíÖåÄíàäÖÉ·‚‡ 10ê‡ÒÒÚÓflÌËfl ‚ ‡Î„·Â10.1. åÖíêàäà çÄ ÉêìèèÄïÉÛÔÔÓÈ (G, ⋅, e) ̇Á˚‚‡ÂÚÒfl ÏÌÓÊÂÒÚ‚Ó G Ò ·Ë̇ÌÓÈ ÓÔ‡ˆËÂÈ ⋅, ÍÓÚÓ‡fl ̇Á˚‚‡ÂÚÒfl „ÛÔÔÓ‚ÓÈ ÓÔ‡ˆËÂÈ, ÒÓ‚ÏÂÒÚÌÓ Û‰Ó‚ÎÂÚ‚Ófl˛˘Ë ˜ÂÚ˚ÂÏ ÙÛ̉‡ÏÂÌڇθÌ˚Ï Ò‚ÓÈÒÚ‚‡Ï Á‡Ï˚͇ÌËfl (x ⋅ y ∈ G ‰Îfl β·˚ı x, y ∈ G), ‡ÒÒӈˇÚË‚ÌÓÒÚË(x ⋅ (y ⋅ z) = (x ⋅ y) ⋅ z ‰Îfl β·˚ı x, y, z ∈ G), ÒÛ˘ÂÒÚ‚Ó‚‡ÌËfl ‰ËÌ˘ÌÓ„Ó ˝ÎÂÏÂÌÚ‡(x ⋅ e = e ⋅ x = x ‰Îfl β·Ó„Ó x ∈ G ) Ë ÒÛ˘ÂÒÚ‚Ó‚‡ÌËfl Ó·‡ÚÌÓ„Ó ˝ÎÂÏÂÌÚ‡ (‰Îflβ·Ó„Ó x ∈ G ÒÛ˘ÂÒÚ‚ÛÂÚ x–1 ∈ G, Ú‡ÍÓÈ ˜ÚÓ x ⋅ x–1 = x–1 ⋅ x = e).
Ç ‡‰‰ËÚË‚ÌÓÈ ÙÓÏÂÁ‡ÔËÒË „ÛÔÔ‡ (G, +, 0) fl‚ÎflÂÚÒfl ÏÌÓÊÂÒÚ‚ÓÏ G Ò Ú‡ÍÓÈ ·Ë̇ÌÓÈ ÓÔ‡ˆËÂÈ +, ˜ÚÓËÏÂ˛Ú ÏÂÒÚÓ ÒÎÂ‰Û˛˘Ë ҂ÓÈÒÚ‚‡: x + y ∈ G ‰Îfl β·˚ı x, y ∈ G , x + (y + z) == (x + y) + z ‰Îfl β·˚ı x, y, z ∈ G, x + 0 = 0 + x ‰Îfl β·Ó„Ó x ∈ G, ‰Îfl β·Ó„Ó x ∈ GÒÛ˘ÂÒÚ‚ÛÂÚ –x ∈ G, Ú‡ÍÓÈ ˜ÚÓ x + (–x) = (–x) + x = 0. ÉÛÔÔ‡ (G, ⋅, e) ̇Á˚‚‡ÂÚÒflÍÓ̘ÌÓÈ, ÂÒÎË ÍÓ̘ÌÓ ÏÌÓÊÂÒÚ‚Ó G. ÉÛÔÔ‡ (G, ⋅, e) ̇Á˚‚‡ÂÚÒfl ‡·Â΂ÓÈ, ÂÒÎËÓ̇ ÍÓÏÏÛÚ‡Ú˂̇, Ú.Â. ‡‚ÂÌÒÚ‚Ó x ⋅ y = y ⋅ x ÒÔ‡‚‰ÎË‚Ó ‰Îfl β·˚ı x, y ∈ G.åÌÓ„Ë ËÁ ‡ÒÒχÚË‚‡ÂÏ˚ı ‚ ‰‡ÌÌÓÏ ‡Á‰ÂΠÏÂÚËÍ fl‚Îfl˛ÚÒfl ÏÂÚËÍÓÈÌÓÏ˚ „ÛÔÔ˚ ̇ „ÛÔÔ (G, ⋅, e), Á‡‰‡ÌÌÓÈ Í‡Í|| x ⋅ y–1 ||–1(ËÎË, ËÌÓ„‰‡, Í‡Í || y ⋅ x ||), „‰Â || ⋅ || – ÌÓχ „ÛÔÔ˚, Ú.Â.
ÙÛÌ͈Ëfl || ⋅ ||: G → , ڇ͇fl˜ÚÓ ‰Îfl β·˚ı x, y ∈ G ËÏÂ˛Ú ÏÂÒÚÓ ÒÎÂ‰Û˛˘Ë ҂ÓÈÒÚ‚‡:1) || x || ≥ 0, Ò || x || = 0 ÚÓ„‰‡ Ë ÚÓθÍÓ ÚÓ„‰‡, ÍÓ„‰‡ x = e;2) || x || = || x–1 ||;3) || x ⋅ y || ≤ || x || + | y || (̇‚ÂÌÒÚ‚Ó ÚÂÛ„ÓθÌË͇).Ç ‡‰‰ËÚË‚ÌÓÈ ÙÓÏ Á‡ÔËÒË ÏÂÚË͇ ÌÓÏ˚ „ÛÔÔ˚ ̇ „ÛÔÔ (G, +, 0) ÓÔ‰ÂÎflÂÚÒfl Í‡Í || x + (–y) || = || x – y || ËÎË ËÌÓ„‰‡ Í‡Í || (–y) + x ||.èÓÒÚÂȯËÏ ÔËÏÂÓÏ ÏÂÚËÍË ÌÓÏ˚ „ÛÔÔ˚ fl‚ÎflÂÚÒfl ·ËËÌ‚‡Ë‡ÌÚ̇fl ÛθڇÏÂÚË͇ (ËÌÓ„‰‡  ̇Á˚‚‡˛Ú ı˝ÏÏË̄ӂÓÈ ÏÂÚËÍÓÈ) || x ⋅ y–1 ||H, „‰Â || x ||H = 1‰Îfl x ≠ e Ë || e ||H = 0.ÅËËÌ‚‡Ë‡ÌÚ̇fl ÏÂÚË͇åÂÚË͇ (‚ Ó·˘ÂÏ ÒÎÛ˜‡Â – ÔÓÎÛÏÂÚË͇) d ̇ „ÛÔÔ (G , ⋅ , e) ̇Á˚‚‡ÂÚÒfl·ËËÌ‚‡Ë‡ÌÚÌÓÈ, ÂÒÎË ‡‚ÂÌÒÚ‚Ód(x, y) = d(x ⋅ z, y ⋅ z) = d(z ⋅ x, z ⋅ y)ÒÔ‡‚‰ÎË‚Ó ‰Îfl β·˚ı x, y, z ∈ G (ÒÏ.
àÌ‚‡Ë‡ÌÚ̇fl ÏÂÚË͇ ÔÂÂÌÓÒ‡). ã˛·‡flÏÂÚË͇ ÌÓÏ˚ „ÛÔÔ˚ ̇ ‡·Â΂ÓÈ „ÛÔÔ fl‚ÎflÂÚÒfl ·Ë‚‡Ë‡ÌÚÌÓÈ.åÂÚË͇ (‚ Ó·˘ÂÏ ÒÎÛ˜‡Â – ÔÓÎÛÏÂÚË͇) d ̇ „ÛÔÔ (G, ⋅, e) ̇Á˚‚‡ÂÚÒfl Ô‡‚ÓËÌ‚‡Ë‡ÌÚÌÓÈ, ÂÒÎË ‡‚ÂÌÒÚ‚Ó d(x, y) = d (z ⋅ x , z ⋅ y) ÒÔ‡‚‰ÎË‚Ó ‰Îfl β·˚ıx, y, z ∈ G, Ú.Â. ÓÔ‡ˆËfl Ô‡‚Ó„Ó ÛÏÌÓÊÂÌËfl ̇ ˝ÎÂÏÂÌÚ z fl‚ÎflÂÚÒfl ‰‚ËÊÂÌËÂÏÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ (G, d). ã˛·‡fl ÏÂÚË͇ ÌÓÏ˚ „ÛÔÔ˚, ÓÔ‰ÂÎflÂχflÍ‡Í || x ⋅ y–1 ||, fl‚ÎflÂÚÒfl Ô‡‚ÓËÌ‚‡Ë‡ÌÚÌÓÈ.169É·‚‡ 10.