Е. Деза_ М.М. Деза. Энциклопедический словарь расстояний (2008) (1185330), страница 45
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ÖÒÎË, ·ÓΠÚÓ„Ó, c1 = ⋅⋅⋅ = c k = 1, ÚÓ ËÏÂÂÏ k-ÌÓÏÛäË î‡Ì‡.åÂÚË͇ ÌÓÏ˚ äË î‡Ì‡ÑÎfl k ∈ , k ≤ min{m, n} ÏÂÚËÍÓÈ ÌÓÏ˚ äË î‡Ì‡ fl‚ÎflÂÚÒfl ÏÂÚË͇ ÌÓÏ˚χÚˈ˚ ̇ Mm,n, ÓÔ‰ÂÎÂÌ̇fl ͇Ík|| A − B ||KF,k„‰Â || ⋅ ||KF – k-ÌÓχ äË î‡Ì‡ ̇ M m,n. ÑÎfl χÚˈ˚ A ∈ M m,n Ó̇ ÓÔ‰ÂÎflÂÚÒfl ͇ÍÒÛÏχ  Ԃ˚ı k ÒËÌ„ÛÎflÌ˚ı Á̇˜ÂÌËÈ:kk=|| A ||KF∑ si ( A).i =1ÑÎfl k = 1 Ï˚ ÔÓÎÛ˜‡ÂÏ ÒÔÂÍڇθÌÛ˛ ÌÓÏÛ.
ÑÎfl k = min{m, n} ËÏÂÂÏ ÒÎÂ‰Ó‚Û˛ÌÓÏÛ.åÂÚË͇ ÌÓÏ˚ ò‡ÚÂ̇ÖÒÎË ‰‡ÌÓ 1 ≤ p < ∞, ÚÓ ÏÂÚË͇ ÌÓÏ˚ ò‡ÚÂ̇ ÂÒÚ¸ ÏÂÚË͇ ÌÓÏ˚ χÚˈ˚ ̇Mm,n, ÓÔ‰ÂÎÂÌ̇fl ͇Íp|| A − B ||Sch,p„‰Â || ⋅ ||Sch – -ÌÓχ ò‡ÚÂ̇ ̇ Mm,n. ÑÎfl χÚˈ˚ A ∈ M m,n Ó̇ ÓÔ‰ÂÎflÂÚÒfl ͇ÍÍÓÂ̸ -È ÒÚÂÔÂÌË ËÁ ÒÛÏÏ˚ -ı ÒÚÂÔÂÌÂÈ ‚ÒÂı  ÒËÌ„ÛÎflÌ˚ı Á̇˜ÂÌËÈ:||pA ||Sch= min{m, n} p si ( A) i =1∑1/ p.ÑÎfl p = 2 Ï˚ ÔÓÎÛ˜‡ÂÏ ÌÓÏÛ îÓ·ÂÌËÛÒ‡, ‡ ‰Îfl p = 1 – ÒÎÂ‰Ó‚Û˛ ÌÓÏÛ.åÂÚË͇ ÒΉӂÓÈ ÌÓÏ˚åÂÚËÍÓÈ ÒΉӂÓÈ ÌÓÏ˚ ̇Á˚‚‡ÂÚÒfl ÏÂÚË͇ ÌÓÏ˚ χÚˈ˚ ̇ Mm,n, ÓÔ‰ÂÎÂÌ̇fl Í‡Í ÒÛÏχ ‚ÒÂı  ÒËÌ„ÛÎflÌ˚ı Á̇˜ÂÌËÈ:|| A – B ||tr,„‰Â || ⋅ ||tr – ÒΉӂ‡fl ÌÓχ ̇ M m,n.
ÑÎfl χÚˈ˚ A ∈ M m,n Ó̇ ÓÔ‰ÂÎflÂÚÒfl ͇ÍÒÛÏχ ‚ÒÂı  ÒËÌ„ÛÎflÌ˚ı Á̇˜ÂÌËÈ:min{m, n}|| A ||tr =∑i =1si ( A).198ó‡ÒÚ¸ III. ê‡ÒÒÚÓflÌËfl ‚ Í·ÒÒ˘ÂÒÍÓÈ Ï‡ÚÂχÚËÍÂåÂÚË͇ êÓÁÂÌ·Î˛Ï‡–ñÙ‡Òχ̇èÛÒÚ¸ M m,n( q ) – ÏÌÓÊÂÒÚ‚Ó ‚ÒÂı m × n χÚˈ Ò ˝ÎÂÏÂÌÚ‡ÏË ËÁ ÍÓ̘ÌÓ„Ó ÔÓÎfl q . çÓχ êÓÁÂÌ·Î˛Ï‡–ñÙ‡Òχ̇ || ⋅ ||RT ̇ Mm,n( q ) ÓÔ‰ÂÎflÂÚÒfl ÒÎÂ‰Û˛˘ËÏ Ó·‡ÁÓÏ: ÂÒÎË m = 1 Ë a = (ξ1 , ξ2 ,…, ξn ) ∈ M 1,n( q ), ÚÓ || 01,n || RT = 0 Ë || a || RT = max{i|ξi ≠ 0}‰Îfl a ≠ 01,n; ÂÒÎË A = (a 1 ,…, a m)T ∈ M m,n( q ), a j ∈ M1,n( q ), 1 ≤ j ≤ m , ÚÓm|| A ||RT =∑|| a j ||RT .j =1åÂÚËÍÓÈ êÓÁÂÌ·Î˛Ï‡–ñÙ‡Òχ̇ ([RoTs96]) ̇Á˚‚‡ÂÚÒfl ÏÂÚË͇ ÌÓÏ˚χÚˈ˚ (̇ Ò‡ÏÓÏ ‰ÂΠÛθڇÏÂÚË͇) ̇ Mm,n( q ), ÓÔ‰ÂÎÂÌ̇fl ͇Í|| A – B ||RT.ì„ÎÓ‚Ó ‡ÒÒÚÓflÌË ÏÂÊ‰Û ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ÏËê‡ÒÒÏÓÚËÏ „‡ÒÒχÌÓ‚Ó ÔÓÒÚ‡ÌÒÚ‚Ó G(m, n) ‚ÒÂı n-ÏÂÌ˚ı ÔÓ‰ÔÓÒÚ‡ÌÒڂ‚ÍÎˉӂ‡ ÔÓÒÚ‡ÌÒÚ‚‡ m; ÓÌÓ fl‚ÎflÂÚÒfl ÍÓÏÔ‡ÍÚÌ˚Ï ËχÌÓ‚˚Ï ÏÌÓ„ÓÓ·‡ÁËÂχÁÏÂÌÓÒÚË n(m–n).ÖÒÎË ËϲÚÒfl ‰‚‡ ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ A, B ∈ G ( m, n), ÚÓ „·‚Ì˚ ۄÎ˚π≥ θ1 ≥ ⋅⋅⋅ ≥ θ n ≥ 0 ÏÂÊ‰Û ÌËÏË ÓÔ‰ÂÎfl˛ÚÒfl (‰Îfl k = 1,…, n) Ë̉ÛÍÚË‚ÌÓ Í‡Í2cos θ k = max max x T y = ( x k )T y k ,x ∈A y ∈BÂÒÎË ‚˚ÔÓÎÌfl˛ÚÒfl ÛÒÎÓ‚Ëfl || x ||2 =|| y ||2 = 1, x T x i = 0, y T y i = 0 ‰Îfl 1 ≤ i ≤ k – 1, „‰Â|| ⋅ ||2 – ‚ÍÎˉӂ‡ ÌÓχ.
É·‚Ì˚ ۄÎ˚ ÏÓ„ÛÚ Á‡‰‡‚‡Ú¸Òfl Ú‡ÍÊ ˜ÂÂÁ ÓÚÓÌÓÏËÓ‚‡ÌÌ˚ χÚˈ˚ Q A Ë Q B, ̇ ÍÓÚÓ˚ ̇ÚflÌÛÚ˚ ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ Ä Ë ÇÒÓÓÚ‚ÂÚÒÚ‚ÂÌÌÓ: ËÏÂÌÌÓ n ÛÔÓfl‰Ó˜ÂÌÌ˚ı ÒËÌ„ÛÎflÌ˚ı Á̇˜ÂÌËÈ Ï‡Úˈ˚QAQB ∈ Mn ÏÓ„ÛÚ ·˚Ú¸ Á‡‰‡Ì˚ Í‡Í cosθ1,…, cosθn.ÉÂÓ‰ÂÁ˘ÂÒÍÓ ‡ÒÒÚÓflÌË ÏÂÊ‰Û ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ÏË Ä Ë Ç ÓÔ‰ÂÎflÂÚÒfl (ÔÓÇÓÌ„Û, 1967) ͇Ín2∑ θi2 .i =1ê‡ÒÒÚÓflÌË å‡ÚË̇ ÏÂÊ‰Û ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ÏË Ä Ë Ç Á‡‰‡ÂÚÒfl ͇Ínln∏i =11.cos 2 θ iÖÒÎË ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ Ô‰ÒÚ‡‚Îfl˛Ú ‡‚ÚÓ„ÂÒÒË‚Ì˚ ÏÓ‰ÂÎË, ÚÓ ‡ÒÒÚÓflÌËÂå‡ÚË̇ ÏÓÊÂÚ ‚˚‡Ê‡Ú¸Òfl ÔÓÒ‰ÒÚ‚ÓÏ ÍÂÔÒÚ‡ ‡‚ÚÓÍÓÂÎflˆËÓÌÌÓÈ ÙÛÌ͈ËË˝ÚËı ÏÓ‰ÂÎÂÈ (ÒÏ.
äÂÔÒڇθÌÓ ‡ÒÒÚÓflÌË å‡ÚË̇, „Î. 21).ê‡ÒÒÚÓflÌË ÄÁËÏÓ‚‡ ÏÂÊ‰Û ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ÏË Ä Ë Ç Á‡‰‡ÂÚÒfl ͇Íθ1 .éÌÓ ÏÓÊÂÚ ·˚Ú¸ ‚˚‡ÊÂÌÓ Ú‡ÍÊ ˜ÂÂÁ ÙËÌÒÎÂÓ‚Û ÏÂÚËÍÛ Ì‡ ÏÌÓ„ÓÓ·‡ÁËËG(m, n).ê‡ÒÒÚÓflÌË ÔÓÔÛÒ͇ ÏÂÊ‰Û ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ÏË Ä Ë Ç ÓÔ‰ÂÎflÂÚÒfl ͇Ísinθ1.É·‚‡ 12. ê‡ÒÒÚÓflÌËfl ̇ ˜ËÒ·ı, ÏÌÓ„Ó˜ÎÂ̇ı Ë Ï‡Úˈ‡ı199éÌÓ ÏÓÊÂÚ ‚˚‡Ê‡Ú¸Òfl Ú‡ÍÊ ‚ ÚÂÏË̇ı ÓÚÓ„Ó̇θÌ˚ı ÓÔ‡ÚÓÓ‚ ÔÓÂÍÚËÓ‚‡ÌËfl Í‡Í l2-ÌÓχ ‡ÁÌÓÒÚË ÓÔ‡ÚÓÓ‚ ÔÓÂÍÚËÓ‚‡ÌËfl ̇ Ä Ë Ç ÒÓÓÚ‚ÂÚÒÚ‚ÂÌÌÓ.
åÌÓ„Ë ‚‡Ë‡ˆËË ˝ÚÓ„Ó ‡ÒÒÚÓflÌËfl ÔËÏÂÌfl˛ÚÒfl ‚ ÚÂÓËË ÛÔ‡‚ÎÂÌËfl(ÒÏ. åÂÚË͇ ÔÓÔÛÒ͇, „Î. 18).ê‡ÒÒÚÓflÌË îÓ·ÂÌËÛÒ‡ ÏÂÊ‰Û ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚‡ÏË Ä Ë Ç ÓÔ‰ÂÎflÂÚÒfl ͇Ín2∑sin 2 θ i .i =1éÌÓ ÏÓÊÂÚ ·˚Ú¸ ‚˚‡ÊÂÌÓ Ú‡ÍÊ ‚ ÚÂÏË̇ı ÓÚÓ„Ó̇θÌ˚ı ÓÔ‡ÚÓÓ‚ ÔÓÂÍÚËÓ‚‡ÌËfl Í‡Í ÌÓχ îÓ·ÂÌËÛÒ‡ ‡ÁÌÓÒÚË ÓÔ‡ÚÓÓ‚ ÔÓÂÍÚËÓ‚‡ÌËfl ̇ Ä Ë ÇnÒÓÓÚ‚ÂÚÒÚ‚ÂÌÌÓ. Ä̇Îӄ˘ÌÓ ‡ÒÒÚÓflÌËÂ∑sin 2 θ i ̇Á˚‚‡ÂÚÒfl ıÓ‰‡Î¸Ì˚Ïi =1‡ÒÒÚÓflÌËÂÏ.èÓÎÛÏÂÚËÍË Ì‡ ÒıÓ‰ÒÚ‚‡ıëÎÂ‰Û˛˘Ë ‰‚ ÔÓÎÛÏÂÚËÍË ÓÔ‰ÂÎfl˛ÚÒfl ‰Îfl β·˚ı ‰‚Ûı ÒıÓ‰ÒÚ‚ d 1 Ë d2 ̇‰‡ÌÌÓÏ ÍÓ̘ÌÓÏ ÔÓÒÚ‡ÌÒÚ‚Â ï (·ÓΠÚÓ„Ó, ‰Îfl β·˚ı ‰‚Ûı ‰ÂÈÒÚ‚ËÚÂθÌ˚ıÒËÏÏÂÚ˘Ì˚ı χÚˈ).èÓÎÛÏÂÚË͇ ãÂχ̇ (ÒÏ. ‡ÒÒÚÓflÌË äẨ‡Î· ̇ ÔÂÂÒÚ‡Ìӂ͇ı, „Î. 11)ÓÔ‰ÂÎflÂÚÒfl ͇Í| {({x, y},{u, v}) : ( d1 ( x, y) − d1 (u, v)) ( d2 ( x, y) − d2 (u, v)) < 0} |,2 | X | + 1 2 „‰Â ({x, y}, {u, v}) – β·‡fl Ô‡‡ ÌÂÛÔÓfl‰Ó˜ÂÌÌ˚ı Ô‡ {x, y}, {u, v} ˝ÎÂÏÂÌÚÓ‚ x, y, u,v ËÁ ï.èÓÎÛÏÂÚË͇ ä‡ÛÙχ̇ ÓÔ‰ÂÎflÂÚÒfl ͇Í| {({x, y},{u, v}) : ( d1 ( x, y) − d1 (u, v)) )d2 ( x, y) − d2 (u, v)) < 0} |.| {({x, y},{u, v}) : ( d1 ( x, y) − d1 (u, v)) ( d2 ( x, y) − d2 (u, v)) ≠ 0} |É·‚‡ 13ê‡ÒÒÚÓflÌËfl ‚ ÙÛÌ͈ËÓ̇θÌÓÏ ‡Ì‡ÎËÁÂîÛÌ͈ËÓ̇θÌ˚È ‡Ì‡ÎËÁ fl‚ÎflÂÚÒfl ӷ·ÒÚ¸˛ χÚÂχÚËÍË, ÍÓÚÓ‡fl Á‡ÌËχÂÚÒflËÁÛ˜ÂÌËÂÏ ÙÛÌ͈ËÓ̇θÌ˚ı ÔÓÒÚ‡ÌÒÚ‚.
í‡ÍÓ ËÒÔÓθÁÓ‚‡ÌË ÒÎÓ‚‡ ÙÛÌ͈ËÓ̇θÌ˚È ÔÓËÒıÓ‰ËÚ ÓÚ ‚‡Ë‡ˆËÓÌÌÓ„Ó ËÒ˜ËÒÎÂÌËfl, „‰Â ‡ÒÒχÚË‚‡˛ÚÒfl ÙÛÌ͈ËË,‡„ÛÏÂÌÚÓÏ ÍÓÚÓ˚ı fl‚ÎflÂÚÒfl ÙÛÌ͈Ëfl. ç‡ ÒÓ‚ÂÏÂÌÌÓÏ ˝Ú‡Ô Ô‰ÏÂÚÓÏÙÛÌ͈ËÓ̇θÌÓ„Ó ‡Ì‡ÎËÁ‡ Ò˜ËÚ‡ÂÚÒfl ËÁÛ˜ÂÌË ÔÓÎÌ˚ı ÌÓÏËÓ‚‡ÌÌ˚ı ‚ÂÍÚÓÌ˚ıÔÓÒÚ‡ÌÒÚ‚, Ú.Â. ·‡Ì‡ıÓ‚˚ı ÔÓÒÚ‡ÌÒÚ‚. ÑÎfl β·Ó„Ó ‰ÂÈÒÚ‚ËÚÂθÌÓ„Ó ˜ËÒ·ÔËÏÂÓÏ ·‡Ì‡ıÓ‚‡ ÔÓÒÚ‡ÌÒÚ‚‡ fl‚ÎflÂÚÒfl Lp -ÔÓÒÚ‡ÌÒÚ‚Ó ‚ÒÂı ËÁÏÂËÏ˚ı ÔÓãÂ·Â„Û ÙÛÌ͈ËÈ, -fl ÒÚÂÔÂ̸ ‡·ÒÓβÚÌÓ„Ó Á̇˜ÂÌËfl ÍÓÚÓ˚ı ËÏÂÂÚ ÍÓ̘Ì˚ÈËÌÚ„‡Î. ÉËθ·ÂÚÓ‚Ó ÔÓÒÚ‡ÌÒÚ‚Ó fl‚ÎflÂÚÒfl ·‡Ì‡ıÓ‚˚Ï ÔÓÒÚ‡ÌÒÚ‚ÓÏ, ‚ ÍÓÚÓÓÏ ÌÓχ ÔÓÎÛ˜Â̇ ËÁ Ò͇ÎflÌÓ„Ó ÔÓËÁ‚‰ÂÌËfl.
èÓÏËÏÓ ˝ÚÓ„Ó, ‚ ÙÛÌ͈ËÓ̇θÌÓÏ ‡Ì‡ÎËÁ ËÒÒÎÂ‰Û˛ÚÒfl ÌÂÔÂ˚‚Ì˚ ÎËÌÂÈÌ˚ ÓÔ‡ÚÓ˚, ÓÔ‰ÂÎflÂÏ˚Â̇ ·‡Ì‡ıÓ‚˚ı Ë „Ëθ·ÂÚÓ‚˚ı ÔÓÒÚ‡ÌÒÚ‚‡ı.13.1. åÖíêàäà çÄ îìçäñàéçÄãúçõï èêéëíêÄçëíÇÄïèÛÒÚ¸ I ⊂ – ÓÚÍ˚Ú˚È ËÌÚ‚‡Î (Ú.Â. ÌÂÔÛÒÚÓ ҂flÁÌÓ ÓÚÍ˚ÚÓ ÏÌÓÊÂÒÚ‚Ó)‚ . ÑÂÈÒÚ‚ËÚÂθ̇fl ÙÛÌ͈Ëfl f : I → ̇Á˚‚‡ÂÚÒfl ‰ÂÈÒÚ‚ËÚÂθÌÓ ‡Ì‡ÎËÚ˘ÂÒÍÓÈ̇ I, ÂÒÎË Ó̇ ‡ÁÎÓÊËχ ‚ fl‰ íÂÈÎÓ‡ ‚ ÓÚÍ˚ÚÓÈ ÓÍÂÒÚÌÓÒÚË U x 0 ͇ʉÓÈ∞f (n) ( x0 )( x − x 0 ) n ‰Îfl β·Ó„Ó x ∈ U x 0 .
èÛÒÚ¸ D ⊂ –n!n=0ӷ·ÒÚ¸ (Ú.Â. ‚˚ÔÛÍÎÓ ÓÚÍ˚ÚÓ ÏÌÓÊÂÒÚ‚Ó) ‚ . äÓÏÔÎÂÍÒ̇fl ÙÛÌ͈Ëflf : I → ̇Á˚‚‡ÂÚÒfl ÍÓÏÔÎÂÍÒÌÓ ‡Ì‡ÎËÚ˘ÂÒÍÓÈ (ËÎË ÔÓÒÚÓ ‡Ì‡ÎËÚ˘ÂÒÍÓÈ) ̇ D,ÂÒÎË Ó̇ ‡ÁÎÓÊËχ ‚ fl‰ íÂÈÎÓ‡ ‚ ÓÚÍ˚ÚÓÈ ÓÍÂÒÚÌÓÒÚË Í‡Ê‰ÓÈ ÚÓ˜ÍËz0 ∈ D. äÓÏÔÎÂÍÒ̇fl ÙÛÌ͈Ëfl f fl‚ÎflÂÚÒfl ‡Ì‡ÎËÚ˘ÂÒÍÓÈ Ì‡ D ÚÓ„‰‡ Ë ÚÓθÍÓ ÚÓ„‰‡,ÍÓ„‰‡ Ó̇ „ÓÎÓÏÓÙ̇ ̇ D, Ú.Â. ӷ·‰‡ÂÚ ÍÓÏÔÎÂÍÒÌÓÈ ÔÓËÁ‚Ó‰ÌÓÈf (z ) − f (z0 )f ′( z 0 ) = lim‚ ͇ʉÓÈ ÚӘ͠z0 ∈ D.z →z0z − z0ÚÓ˜ÍË x0 ∈ I : f(x ) =∑àÌÚ„‡Î¸Ì‡fl ÏÂÚË͇àÌÚ„‡Î¸ÌÓÈ ÏÂÚËÍÓÈ Ì‡Á˚‚‡ÂÚÒfl L1 -ÏÂÚË͇ ̇ ÏÌÓÊÂÒÚ‚Â C [a, b] ‚ÒÂıÌÂÔÂ˚‚Ì˚ı ‰ÂÈÒÚ‚ËÚÂθÌ˚ı (ÍÓÏÔÎÂÍÒÌ˚ı) ÙÛÌ͈ËÈ Ì‡ ‰‡ÌÌÓÏ ÓÚÂÁÍ [a, b],ÓÔ‰ÂÎÂÌ̇fl ͇Íb∫| f ( x ) − g( x ) | dx.aëÓÓÚ‚ÂÚÒÚ‚Û˛˘Â ÏÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Ó ÒÓ͇˘ÂÌÌÓ Á‡ÔËÒ˚‚‡ÂÚÒfl ͇Í1C[ a, b ] Ë fl‚ÎflÂÚÒfl ·‡Ì‡ıÓ‚˚Ï ÔÓÒÚ‡ÌÒÚ‚ÓÏ.201É·‚‡ 13.
ê‡ÒÒÚÓflÌËfl ‚ ÙÛÌ͈ËÓ̇θÌÓÏ ‡Ì‡ÎËÁÂÇ Ó·˘ÂÏ ÒÎÛ˜‡Â ‰Îfl β·Ó„Ó ÍÓÏÔ‡ÍÚÌÓ„Ó (ËÎË Ò˜ÂÚÌÓ ÍÓÏÔ‡ÍÚÌÓ„Ó) ÚÓÔÓÎӄ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ ï ËÌÚ„‡Î¸ÌÛ˛ ÏÂÚËÍÛ ÏÓÊÌÓ Á‡‰‡Ú¸ ̇ ÏÌÓÊÂÒÚ‚Â ‚ÒÂıÌÂÔÂ˚‚Ì˚ı ÙÛÌ͈ËÈ f : X → () ͇Í∫| f ( x ) − g( x ) | dx.XꇂÌÓÏÂ̇fl ÏÂÚË͇ꇂÌÓÏÂ̇fl ÏÂÚË͇ (ËÎË sup-ÏÂÚË͇) ÂÒÚ¸ L-ÏÂÚË͇ ̇ ÏÌÓÊÂÒÚ‚Â C [a, b]‚ÒÂı ‰ÂÈÒÚ‚ËÚÂθÌ˚ı (ÍÓÏÔÎÂÍÒÌ˚ı) ÌÂÔÂ˚‚Ì˚ı ÙÛÌ͈ËÈ Ì‡ ‰‡ÌÌÓÏ ÓÚÂÁÍÂ[a, b], ÓÔ‰ÂÎÂÌ̇fl ͇Ísup | f ( x ) − g( x ) | .x ∈[ a, b ]ëÓÓÚ‚ÂÚÒÚ‚Û˛˘Â ÏÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Ó ÒÓ͇˘ÂÌÌÓ Á‡ÔËÒ˚‚‡ÂÚÒfl ͇ÍË fl‚ÎflÂÚÒfl ·‡Ì‡ıÓ‚˚Ï ÔÓÒÚ‡ÌÒÚ‚ÓÏ.C[∞a, b ]é·Ó·˘ÂÌËÂÏ C[∞a, b ] fl‚ÎflÂÚÒfl ÔÓÒÚ‡ÌÒÚ‚Ó ÌÂÔÂ˚‚Ì˚ı ÙÛÌ͈ËÈ C(X), Ú.Â.ÏÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Ó Ì‡ ÏÌÓÊÂÒÚ‚Â ‚ÒÂı ÌÂÔÂ˚‚Ì˚ı (‚ Ó·˘ÂÏ ÒÎÛ˜‡Â,Ó„‡Ì˘ÂÌÌ˚ı) ÙÛÌ͈ËÈ f : X → ÚÓÔÓÎӄ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ ï Ò L ∞-ÏÂÚËÍÓÈsup | f ( x ) − g( x ) | .x ∈XÑÎfl ÒÎÛ˜‡fl ÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ C(X, Y) ÌÂÔÂ˚‚Ì˚ı (‚ Ó·˘ÂÏ ÒÎÛ˜‡ÂÓ„‡Ì˘ÂÌÌ˚ı) ÙÛÌ͈ËÈ f : X → Y ËÁ Ó‰ÌÓ„Ó ÏÂÚ˘ÂÒÍÓ„Ó ÍÓÏÔ‡ÍÚ‡ (X, d X) ‚ ‰Û„ÓÈ(X, d Y) sup-ÏÂÚË͇ ÏÂÊ‰Û ‰‚ÛÏfl ÙÛÌ͈ËflÏË f, g ∈ C(X, Y) ÓÔ‰ÂÎflÂÚÒfl ͇Ísup dY ( f ( x ), g( x )).
åÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Ó C[∞a, b ] Ë ÏÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Óx ∈XC[1a, b ] fl‚Îfl˛ÚÒfl ‚‡ÊÌÂȯËÏË ÒÎÛ˜‡flÏË ÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ C[pa, b ] , 1 ≤ p ≤ ∞ḃ ÏÌÓÊÂÒÚ‚Â C[a, b] Ò L p -ÏÂÚËÍÓÈ | f ( x ) − g( x ) | p dx afl‚ÎflÂÚÒfl ÔËÏÂÓÏ L p -ÔÓÒÚ‡ÌÒÚ‚‡.∫1/ p.
èÓÒÚ‡ÌÒÚ‚Ó C[pa, b ]ê‡ÒÒÚÓflÌË ÒÓ·‡ÍÓ‚Ó‰‡ÑÎfl ÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ (X, d) ‡ÒÒÚÓflÌËÂÏ ÒÓ·‡ÍÓ‚Ó‰‡ ̇Á˚‡‚ÂÚÒflÏÂÚË͇ ̇ ÏÌÓÊÂÒÚ‚Â ‚ÒÂı ÙÛÌ͈ËÈ f : [0, 1] → X, ÓÔ‰ÂÎÂÌ̇fl ͇Íinf sup d ( f (t ), g(σ(t )),σ t ∈[ 0,1]„‰Â σ: [0, 1] → [0, 1] ÂÒÚ¸ ÌÂÔÂ˚‚̇fl ÏÓÌÓÚÓÌÌÓ ‚ÓÁ‡ÒÚ‡˛˘‡fl ÙÛÌ͈Ëfl, ڇ͇fl˜ÚÓ σ(0) = 0, σ(1) = 1. чÌ̇fl ÏÂÚË͇ fl‚ÎflÂÚÒfl ˜‡ÒÚÌ˚Ï ÒÎÛ˜‡ÂÏ ÏÂÚËÍË î¯Â.èËÏÂÌflÂÚÒfl ‰Îfl ËÁÏÂÂÌËfl ‡ÒÒÚÓflÌËÈ ÏÂÊ‰Û ÍË‚˚ÏË.åÂÚË͇ ÅÓ‡èÛÒÚ¸ – ÏÂÚ˘ÂÒÍÓ ÔÓÒÚ‡ÌÒÚ‚Ó Ò ÏÂÚËÍÓÈ ρ. çÂÔÂ˚‚̇fl ÙÛÌ͈Ëflf : → ̇Á˚‚‡ÂÚÒfl ÔÓ˜ÚË ÔÂËӉ˘ÂÒÍÓÈ, ÂÒÎË ‰Îfl Í‡Ê‰Ó„Ó ε > 0 ÒÛ˘ÂÒÚ‚ÛÂÚl = l(ε) > 0, Ú‡ÍÓ ˜ÚÓ Í‡Ê‰˚È ËÌÚ‚‡Î [t0, t0 + l(ε)] ÒÓ‰ÂÊËÚ ÔÓ ÏÂ̸¯ÂÈ Ï ӉÌÓ˜ËÒÎÓ τ, ‰Îfl ÍÓÚÓÓ„Ó ρ(f(t), f(t + τ)) < ε, –∞ < t < +∞.åÂÚËÍÓÈ ÅÓ‡ ̇Á˚‚‡ÂÚÒfl ÏÂÚË͇ ÌÓÏ˚ || f – g || ̇ ÏÌÓÊÂÒÚ‚Â Äê ‚ÒÂı ÔÓ˜ÚËÔÂËӉ˘ÂÒÍËı ÙÛÌ͈ËÈ, Á‡‰‡Ì̇fl ÌÓÏÓÈ|| f || = sup | f (t ) | .−∞< t < +∞202ó‡ÒÚ¸ III.
ê‡ÒÒÚÓflÌËfl ‚ Í·ÒÒ˘ÂÒÍÓÈ Ï‡ÚÂχÚËÍÂíÂÏ Ò‡Ï˚Ï ÔÓÒÚ‡ÌÒÚ‚Ó Äê Ô‚‡˘‡ÂÚÒfl ‚ ·‡Ì‡ıÓ‚Ó ÔÓÒÚ‡ÌÒÚ‚Ó. çÂÍÓÚÓ˚ ӷӷ˘ÂÌËfl ÔÓ˜ÚË ÔÂËӉ˘ÂÒÍËı ÙÛÌ͈ËÈ ·˚ÎË ÔÓÎÛ˜ÂÌ˚ Ò ËÒÔÓθÁÓ‚‡ÌËÂωۄËı ÌÓÏ; ÒÏ. ê‡ÒÒÚÓflÌË ëÚÂÔ‡ÌÓ‚‡, ê‡ÒÒÚÓflÌË ǽÈÎfl, ê‡ÒÒÚÓflÌË ÅÂÒËÍӂ˘‡Ë åÂÚËÍÛ ÅÓı̇.ê‡ÒÒÚÓflÌË ëÚÂÔ‡ÌÓ‚‡ê‡ÒÒÚÓflÌË ëÚÂÔ‡ÌÓ‚‡ – ‡ÒÒÚÓflÌË ̇ ÏÌÓÊÂÒÚ‚Â ‚ÒÂı ËÁÏÂËÏ˚ı ÙÛÌ͈ËÈf : → Ò ÒÛÏÏËÛÂÏÓÈ -È ÒÚÂÔÂ̸˛ ̇ ͇ʉÓÏ Ó„‡Ì˘ÂÌÌÓÏ ËÌÚ„‡ÎÂ,ÓÔ‰ÂÎÂÌÌÓÂ Í‡Í 1 x +lsup| f ( x ) − g( x ) | p dx x ∈ lx1/ p∫.ê‡ÒÒÚÓflÌË ÇÂÈÎfl – ‡ÒÒÚÓflÌË ̇ ÚÓÏ Ê ÏÌÓÊÂÒÚ‚Â, Á‡‰‡ÌÌÓÂ Í‡Í 1 x +llim sup | f ( x ) − g( x ) | p dx l →∞ x ∈ l x1/ p∫.ùÚËÏ ‡ÒÒÚÓflÌËflÏ ÒÓÓÚ‚ÂÚÒÚ‚Û˛Ú Ó·Ó·˘ÂÌÌ˚ ÔÓ˜ÚË ÔÂËӉ˘ÂÒÍË ÙÛÌ͈ËËëÚÂÔ‡ÌÓ‚‡ Ë Ç˝ÈÎfl.ê‡ÒÒÚÓflÌË ÅÂÒËÍӂ˘‡ê‡ÒÒÚÓflÌËÂÏ ÅÂÒËÍӂ˘‡ ̇Á˚‚‡ÂÚÒfl ‡ÒÒÚÓflÌË ̇ ÏÌÓÊÂÒÚ‚Â ‚ÒÂı ËÁÏÂËÏ˚ıÙÛÌ͈ËÈ f : → Ò ÒÛÏÏËÛÂÏÓÈ -È ÒÚÂÔÂ̸˛ ̇ ͇ʉÓÏ Ó„‡Ì˘ÂÌÌÓÏËÌÚ„‡ÎÂ, ÓÔ‰ÂÎÂÌÌÓ ͇Í1 lim T →∞ 2TT∫−T| f ( x ) − g( x ) | dx p1/ p.ùÚËÏ ‡ÒÒÚÓflÌËflÏ ÒÓÓÚ‚ÂÚÒÚ‚Û˛Ú Ó·Ó·˘ÂÌÌ˚ ÔÓ˜ÚË ÔÂËӉ˘ÂÒÍË ÙÛÌ͈ËËÅÂÒËÍӂ˘‡.• åÂÚË͇ ÅÓı̇ÑÎfl ÔÓÒÚ‡ÌÒÚ‚‡ Ò ÏÂÓÈ (Ω, , µ) ·‡Ì‡ıÓ‚‡ ÔÓÒÚ‡ÌÒÚ‚‡ (V, || ⋅ ||V) Ë 1 ≤ p ≤ ∞ÔÓÒÚ‡ÌÒÚ‚ÓÏ ÅÓı̇ (ËÎË ÔÓÒÚ‡ÌÒÚ‚ÓÏ ã·„‡–ÅÓı̇) ̇Á˚‚‡ÂÚÒflÏÌÓÊÂÒÚ‚Ó ‚ÒÂı ËÁÏÂËÏ˚ı ÙÛÌ͈ËÈ f : Ω → V, Ú‡ÍËı ˜ÚÓ || f || L p ( Ω, V ) < ∞.
á‰ÂÒ¸ÌÓχ ÅÓı̇ | f || L p ( Ω, V ) ÓÔ‰ÂÎflÂÚÒfl Í‡Í || f (ω ) ||Vp dµ(ω )ΩÍ‡Í essω ∈Ω || f (ω ) ||V . ‰Îfl p = ∞.∫1/ p‰Îfl 1 ≤ p < ∞ Ë-ÏÂÚË͇ Å„χ̇èË ‰‡ÌÌÓÏ 1 ≤ p ≤ ∞ ÔÛÒÚ¸ L p (∆ ) – Lp-ÔÓÒÚ‡ÌÒÚ‚Ó Î·„ӂ˚ı ËÁÏÂËÏ˚ıÙÛÌ͈ËÈ f ̇ ‰ËÌ˘ÌÓÏ ‰ËÒÍ ∆ = {z ∈ :| z |< 1} c || f || p = | f ( z ) | p µ( dz )∆∫1/ p< ∞.èÓÒÚ‡ÌÒÚ‚ÓÏ Å„χ̇ Lap ( ∆ ) ̇Á˚‚‡ÂÚÒfl ÔÓ‰ÔÓÒÚ‡ÌÒÚ‚Ó ÔÓÒÚ‡ÌÒÚ‚‡L p (∆), ÒÓÒÚÓfl˘Â ËÁ ‡Ì‡ÎËÚ˘ÂÒÍËı ÙÛÌ͈ËÈ, Ë -ÏÂÚËÍÓÈ Å„χ̇ ̇Á˚‚‡ÂÚÒfl203É·‚‡ 13.