Е. Деза_ М.М. Деза. Энциклопедический словарь расстояний (2008) (1185330), страница 49
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䂇ÁˇÒÒÚÓflÌË Å„χ̇).f-‡ÒıÓʉÂÌË óËÁ‡‡f-‡ÒıÓʉÂÌË óËÁ‡‡ ÂÒÚ¸ ÙÛÌ͈Ëfl ̇ ÏÌÓÊÂÒÚ‚Â ×, ÓÔ‰ÂÎÂÌ̇fl ͇Í∑x p ( x) p2 ( x ) f 1 , p2 ( x ) „‰Â f: ≥0 → – ‚˚ÔÛÍ·fl ÙÛÌ͈Ëfl.ëÎÛ˜‡Ë f(t ) = t ln t Ë f(t) = (t – 1)2 /2 ÒÓÓÚ‚ÂÚÒÚ‚Û˛Ú ‡ÒÒÚÓflÌ˲ äÛÎη‡Í‡–ãÂȷ· Ë 2 -‡ÒÒÚÓflÌ˲, Û͇Á‡ÌÌ˚ı ÌËÊÂ. ëÎÛ˜‡È f(t) = | t – 1 | ÒÓÓÚ‚ÂÚÒÚ‚ÛÂÚL1 -ÏÂÚËÍ ÏÂÊ‰Û ÔÎÓÚÌÓÒÚflÏË, ‡ ÒÎÛ˜‡È f (t ) = 4 1 − t (Ú‡Í ÊÂ Í‡Í Ë ÒÎÛ˜‡È()f (t ) = 2(t + 1) − 4 t ) ÒÓÓÚ‚ÂÚÒÚ‚ÛÂÚ Í‚‡‰‡ÚÛ ÏÂÚËÍË ïÂÎÎË̉ʇ.É·‚‡ 14. ê‡ÒÒÚÓflÌËfl ‚ ÚÂÓËË ‚ÂÓflÚÌÓÒÚÂÈ 219èÓÎÛÏÂÚËÍË ÏÓ„ÛÚ ·˚Ú¸ ÔÓÎÛ˜ÂÌ˚ Ú‡Í ÊÂ, Í‡Í Í‚‡‰‡ÚÌ˚È ÍÓÂ̸ f-‡ÒıÓʉÂÌËfl óËÁ‡‡ ‚ ÒÎÛ˜‡flı f (t ) = (t − 1)2 /(t + 1) (ÔÓÎÛÏÂÚË͇ LJʉ˚–äÛÒ‡), f (t ) == | t a − 1 |1 / a Ò 0 < a ≤ 1 (ÔÓÎÛÏÂÚË͇ å‡ÚÛ¯ËÚ˚) Ë f (t ) =(t a + 1)1 / a − 2 (1− a ) / a (t + 1)1 −1/ a(ÔÓÎÛÏÂÚË͇ éÒÚÂÂÈı‡).èÓ‰Ó·ÌÓÒÚ¸ ‰ÓÒÚÓ‚ÂÌÓÒÚËèÓ‰Ó·ÌÓÒÚ¸ ‰ÓÒÚÓ‚ÂÌÓÒÚË (ËÎË ÍÓ˝ÙÙˈËÂÌÚ Åı‡ÚÚ‡˜‡¸fl, ‡ÙÙËÌÌÓÒÚ¸ïÂÎÎË̉ʇ) ̇ ÓÔ‰ÂÎflÂÚÒfl ͇Íρ( P1 , P2 ) =∑p1 ( x ) p2 ( x ).xåÂÚË͇ ïÂÎÎË̉ÊÂ‡Ç ÚÂÏË̇ı ÔÓ‰Ó·ÌÓÒÚË ‰ÓÒÚÓ‚ÂÌÓÒÚË, ÏÂÚË͇ ïÂÎÎË̉ʇ (ËÎË ÏÂÚË͇ïÂÎÎË̉ʇ–ä‡ÍÛÚ‡ÌË) ̇ ÓÔ‰ÂÎflÂÚÒfl ͇Í2∑(x)2p1 ( x ) − p2 ( x ) 1/ 2= 2(1 − ρ( P1 , P2 ))1 / 2 .ùÚÓ – L2 -ÏÂÚË͇ ÏÂÊ‰Û Í‚‡‰‡ÚÌ˚ÏË ÍÓÌflÏË ÙÛÌ͈ËÈ ÔÎÓÚÌÓÒÚË.èÓ‰Ó·ÌÓÒÚ¸ Ò‰ÌÂ„Ó „‡ÏÓÌ˘ÂÒÍÓ„ÓèÓ‰Ó·ÌÓÒÚ¸ Ò‰ÌÂ„Ó „‡ÏÓÌ˘ÂÒÍÓ„Ó ÂÒÚ¸ ÔÓ‰Ó·ÌÓÒÚ¸ ̇ , ÓÔ‰ÂÎÂÌ̇fl ͇Í2∑ p1 (1x ) + p2 2 ( x ) .p ( x) p ( x)xê‡ÒÒÚÓflÌË 1 Åı‡ÚÚ‡˜‡¸flÇ ÚÂÏË̇ı ÔÓ‰Ó·ÌÓÒÚË ‰ÓÒÚÓ‚ÂÌÓÒÚË, ‡ÒÒÚÓflÌË 1 Åı‡ÚÚ‡˜‡¸fl ̇ ÓÔ‰ÂÎflÂÚÒfl ͇Í(arccos ρ(P1 , P2 )) 2 .쉂ÓÂÌË ڇÍÓ„Ó ‡ÒÒÚÓflÌËfl ÔËÏÂÌflÂÚÒfl Ú‡ÍÊ ‚ ÒÚ‡ÚËÒÚËÍÂ Ë Ï‡¯ËÌÌÓÏÓ·Û˜ÂÌËË, „‰Â ÓÌÓ Ì‡Á˚‚‡ÂÚÒfl ‡ÒÒÚÓflÌËÂÏ î˯‡.ê‡ÒÒÚÓflÌË 2 Åı‡ÚÚ‡˜‡¸flÇ ÚÂÏË̇ı ÔÓ‰Ó·ÌÓÒÚË ‰ÓÒÚÓ‚ÂÌÓÒÚË, ‡ÒÒÚÓflÌË 2 Åı‡ÚÚ‡˜‡¸fl ̇ ÓÔ‰ÂÎflÂÚÒfl ͇͖ln ρ(P1 , P2 ).2 -‡ÒÒÚÓflÌËÂ2 -‡ÒÒÚÓflÌË (ËÎË 2 -‡ÒÒÚÓflÌË çÂÈχ̇) ÂÒÚ¸ Í‚‡ÁˇÒÒÚÓflÌË ̇ , ÓÔ‰ÂÎÂÌÌÓ ͇Í∑x( p1 ( x ) − p2 ( x ))2.p2 ( x )220ó‡ÒÚ¸ III.
ê‡ÒÒÚÓflÌËfl ‚ Í·ÒÒ˘ÂÒÍÓÈ Ï‡ÚÂχÚËÍÂ2 -‡ÒÒÚÓflÌË èËÒÓ̇ ÓÔ‰ÂÎflÂÚÒfl ͇Í∑x( p1 ( x ) − p2 ( x ))2.p1 ( x )ÇÂÓflÚÌÓÒÚ̇fl ÒËÏÏÂÚ˘ÂÒ͇fl 2 -χ ÂÒÚ¸ ‡ÒÒÚÓflÌË ̇ , ÓÔ‰ÂÎÂÌÌÓ ͇Í2∑x( p1 ( x ) − p2 ( x ))2.p1 ( x ) − p2 ( x )ê‡ÒÒÚÓflÌË ‡Á‰ÂÎÂÌËflê‡ÒÒÚÓflÌËÂÏ ‡Á‰ÂÎÂÌËfl ̇Á˚‚‡ÂÚÒfl Í‚‡ÁˇÒÒÚÓflÌË ̇ (‰Îfl β·Ó„Ó Ò˜ÂÚÌÓ„Ó χ), ÓÔ‰ÂÎÂÌÌÓ ͇Íp ( x) max1 − 1 .x p2 ( x ) (ç ÔÛÚ‡Ú¸ Ò ‡ÒÒÚÓflÌËÂÏ ‡Á‰ÂÎÂÌËfl ÏÂÊ‰Û ‚˚ÔÛÍÎ˚ÏË Ú·ÏË.)ê‡ÒÒÚÓflÌË äÛÎη‡Í‡–ãeȷ·ê‡ÒÒÚÓflÌË äÛÎη‡Í‡–ãÂȷ· (ËÎË ÓÚÌÓÒËÚÂθ̇fl ˝ÌÚÓÔËfl, ÓÚÍÎÓÌÂÌËÂËÌÙÓχˆËË, KL-‡ÒÒÚÓflÌËÂ) ÂÒÚ¸ Í‚‡ÁˇÒÒÚÓflÌË ̇ , ÓÔ‰ÂÎÂÌÌÓ ͇ÍKL( P1 , P2 ) = P1 [ln L] =∑p1 ( x ) lnx„‰Â L =p1 ( x ),p2 ( x )p1 ( x )– ÓÚÌÓ¯ÂÌË ԇ‚‰ÓÔÓ‰Ó·Ëfl. ëΉӂ‡ÚÂθÌÓ,p2 ( x )KL( P1 , P2 ) = −∑x( p1 ( x ) ln p2 ( x )) +∑( p1 ( x ) ln p1 ( x )) = H ( P1 , P2 ) − H ( P1 ),x„‰Â H ( P1 ) – ˝ÌÚÓÔËfl P1 , ‡ H ( P1 , P2 ) – ÔÂÂÍeÒÚ̇fl ˝ÌÚÓÔËfl P1 Ë P2 .
ÖÒÎË P2fl‚ÎflÂÚÒfl ÔÓËÁ‚‰ÂÌËÂÏ Ï‡„Ë̇ÎÓ‚ P1 , ÚÓ KL-‡ÒÒÚÓflÌË KL(P1 , P2 ) ̇Á˚‚‡ÂÚÒflp ( x, y)ÍÓ΢ÂÒÚ‚ÓÏ ËÌÙÓχˆËË ò˝ÌÌÓ̇ Ë ‡‚ÌÓp1 ( x, y) ln 1(ÒÏ. ‡Òp1 ( x ) p1 ( y)( x , y ) ∈χ × χ∑ÒÚÓflÌË ò˝ÌÌÓ̇).äÓÒÓ ‡ÒıÓʉÂÌËÂäÓÒÓ ‡ÒıÓʉÂÌË – Í‚‡ÁˇÒÒÚÓflÌË ̇ , ÓÔ‰ÂÎÂÌÌÓ ͇ÍKL( P1 , aP2 + (1 − a) P1 ),„‰Â a ∈ [0, 1] – ÍÓÌÒÚ‡ÌÚ‡ Ë KL – ‡ÒÒÚÓflÌË äÛÎη‡Í‡–ãÂȷ·.
í‡ÍËÏ Ó·‡ÁÓÏ,1ÒÎÛ˜‡È a = 1 ÒÓÓÚ‚ÂÚÒÚ‚ÛÂÚ KL(P 1 , P2 ). äÓÒÓ ‡ÒıÓʉÂÌËÂ Ò a =̇Á˚‚‡ÂÚÒfl2K-‡ÒıÓʉÂÌËÂÏ.É·‚‡ 14. ê‡ÒÒÚÓflÌËfl ‚ ÚÂÓËË ‚ÂÓflÚÌÓÒÚÂÈ 221ê‡ÒıÓʉÂÌË ÑÊÂÙÙËê‡ÒıÓʉÂÌËÂÏ ÑÊÂÙÙË (ËÎË J-‡ÒıÓʉÂÌËÂÏ) ̇Á˚‚‡ÂÚÒfl ÒËÏÏÂÚ˘̇fl ‚ÂÒËfl‡ÒÒÚÓflÌËfl äÛÎη‡Í‡–ãÂȷ·, ÓÔ‰ÂÎÂÌ̇fl ͇ÍKL( P1 , P2 ) + KL( P2 , P1 ) =∑xp1 ( x )p ( x) + p2 ( x ) ln 2 . p1 ( x ) lnp(x)p1 ( x ) 2ÑÎfl P1 → P2 ‡ÒıÓʉÂÌË ÑÊÂÙÙË ‚‰ÂÚ Ò·fl ‡Ì‡Îӄ˘ÌÓ 2 -‡ÒÒÚÓflÌ˲.ê‡ÒıÓʉÂÌË ÑÊÂÌÒÂ̇–ò˝ÌÌÓ̇ê‡ÒıÓʉÂÌË ÑÊÂÌÒÂ̇–ò˝ÌÌÓ̇ ÓÔ‰ÂÎflÂÚÒfl ͇ÍaKL( P1 , P3 ) + (1 − a) KL( P2 , P3 ),„‰Â P3 = aP1 + (1 − a) P2 Ë a ∈ [0, 1] – ÍÓÌÒÚ‡ÌÚ‡ (ÒÏ. èÓ‰Ó·ÌÓÒÚ¸ flÒÌÓÒÚË).ç‡ flÁ˚Í ˝ÌÚÓÔËË H ( P) =∑p( x ) ln p( x ) ‡ÒıÓʉÂÌË ÑÊÂÌÒÂ̇–ò˝ÌÌÓ̇x‡‚ÌÓ H ( aP1 + (1 − a) P2 ) − aH ( P1 ) − (1 − a) H ( P2 ).ê‡ÒÒÚÓflÌË íÓÔÒ ÂÒÚ¸ ÒËÏÏÂÚ˘̇fl ‚ÂÒËfl ‡ÒÒÚÓflÌËfl äÛÎη‡Í‡–ãÂȷ·̇ .
éÌÓ ÓÔ‰ÂÎflÂÚÒfl ͇ÍKL( P1 , P3 ) + KL( P2 , P3 ) =∑xp1 ( x )p ( x) + p2 ( x ) ln 2 , p1 ( x ) lnp3 ( x )p3 ( x ) 1( P1 + P2 ). ê‡ÒÒÚÓflÌË íÓÔÒ ÂÒÚ¸ Û‰‚ÓÂÌÌÓ ‡ÒıÓʉÂÌË ÑÊÂÌÒÂ̇–21ò˝ÌÌÓ̇ Ò a = . çÂÍÓÚÓ˚ ‡‚ÚÓ˚ ËÒÔÓθÁÛ˛Ú ÚÂÏËÌ "‡ÒıÓʉÂÌË ÑÊÂÌÒÂ̇–2ò˝ÌÌÓ̇" ÚÓθÍÓ ‰Îfl ‰‡ÌÌÓÈ ‚Â΢ËÌ˚ ‡. ê‡ÒÒÚÓflÌË ÚÓÊ ÏÂÚËÍÓÈ Ì fl‚ÎflÂÚÒfl,ÌÓ Â„Ó Í‚‡‰‡ÚÌ˚È ÍÓÂ̸ – ÏÂÚË͇.„‰Â P3 =ê‡ÒÒÚÓflÌË Ò‰ÌÂ„Ó ÒÓÔÓÚË‚ÎÂÌËflê‡ÒÒÚÓflÌË Ò‰ÌÂ„Ó ÒÓÔÓÚË‚ÎÂÌËfl ÔÓ ÑÊÂÌÒÂÌÛ–òËχÌÓ‚Ë˜Û ÂÒÚ¸ ÒËÏÏÂÚ˘̇fl ‚ÂÒËfl ‡ÒÒÚÓflÌËfl äÛÎη‡Í‡–ãÂȷ· ̇ . éÌÓ ÓÔ‰ÂÎflÂÚÒfl Í‡Í „‡ÏÓÌ˘ÂÒ͇fl ÒÛÏχ11+ KL( P1 , P2 ) KL( P2 , P1 ) −1(ÒÏ. åÂÚË͇ ÒÓÔÓÚË‚ÎÂÌËfl ‰Îfl „‡ÙÓ‚, „Î. 15).ê‡ÒÒÚÓflÌË ÄÎË–ëË΂Âflê‡ÒÒÚÓflÌË ÄÎË–ëË΂Âfl ÂÒÚ¸ Í‚‡ÁˇÒÒÚÓflÌË ̇ , Á‡‰‡ÌÌÓ ÙÛÌ͈ËÓ̇ÎÓÏf ( P1 [ g( L)]),p1 ( x )– ÓÚÌÓ¯ÂÌË ԇ‚‰ÓÔÓ‰Ó·Ëfl, f – ÌÂÛ·˚‚‡˛˘‡fl ÙÛÌ͈Ëfl, ‡ g – ÌÂÔÂp2 ( x )˚‚̇fl ‚˚ÔÛÍ·fl ÙÛÌ͈Ëfl (ÒÏ.
f-‡ÒıÓʉÂÌË óËÁ‡‡).ëÎÛ˜‡È f(x) = x, g(x ) = x ln x ÒÓÓÚ‚ÂÚÒÚ‚ÛÂÚ ‡ÒÒÚÓflÌ˲ äÛÎη‡Í‡–ãÂȷ·;ÒÎÛ˜‡È f(x) = –ln x, g(x) = x' – ‡ÒÒÚÓflÌ˲ óÂÌÓ‚‡.„‰Â L =222ó‡ÒÚ¸ III. ê‡ÒÒÚÓflÌËfl ‚ Í·ÒÒ˘ÂÒÍÓÈ Ï‡ÚÂχÚËÍÂê‡ÒÒÚÓflÌË óÂÌÓ‚‡ê‡ÒÒÚÓflÌËÂÏ óÂÌÓ‚‡ (ËÎË ÔÂÂÍeÒÚÌÓÈ ˝ÌÚÓÔËÂÈ êÂ̸Ë) ̇Á˚‚‡ÂÚÒfl ‡ÒÒÚÓflÌË ̇ , ÓÔ‰ÂÎÂÌÌÓ ͇Ímax Dt ( P1 , P2 ),t ∈[ 0,1]„‰Â Dt ( P1 , P2 ) = − ln∑( p1 ( x ))t ( p2 ( x ))1− t , ˜ÚÓ ÔÓÔÓˆËÓ̇θÌÓ ‡ÒÒÚÓflÌ˲ êÂ̸Ë.x1ëÎÛ˜‡È t = ÒÓÓÚ‚ÂÚÒÚ‚ÛÂÚ ‡ÒÒÚÓflÌ˲ 2 Åı‡ÚÚ‡˜‡¸fl.2ê‡ÒÒÚÓflÌË êÂ̸Ëê‡ÒÒÚÓflÌË êÂÌ¸Ë (ËÎË ˝ÌÚÓÔËfl êÂÌ¸Ë ÔÓfl‰Í‡ t) ÂÒÚ¸ Í‚‡ÁˇÒÒÚÓflÌË ̇ ,ÓÔ‰ÂÎÂÌÌÓ ͇Í1lnt −1∑xt p ( x) p2 ( x ) 1 , p2 ( x ) „‰Â t ≥ 0, t ≠ 1.è‰ÂÎÓÏ ‡ÒÒÚÓflÌËfl êÂÌ¸Ë ‰Îfl t → 1 fl‚ÎflÂÚÒfl ‡ÒÒÚÓflÌË äÛÎη‡Í‡–ãÂȷ·.1ÑÎfl t = ÔÓÎÓ‚Ë̇ ‡ÒÒÚÓflÌËfl êÂÌ¸Ë ÂÒÚ¸ ‡ÒÒÚÓflÌË 2 Åı‡ÚÚ‡˜‡¸fl (ÒÏ.
f-‡ÒıÓÊ2‰ÂÌË óËÁ‡‡ Ë ‡ÒÒÚÓflÌË óÂÌÓ‚‡).èÓ‰Ó·ÌÓÒÚ¸ flÒÌÓÒÚËèÓ‰Ó·ÌÓÒÚ¸ flÒÌÓÒÚË – ˝ÚÓ ÔÓ‰Ó·ÌÓÒÚ¸ ̇ , ÓÔ‰ÂÎÂÌ̇fl ͇Í( KL( P1 , P3 ) + KL( P2 , P3 )) − ( KL( P1 , P2 ) + KL( P2 , P1 )) ==∑xp2 ( x )p ( x) + p2 ( x ) ln 1 , p1 ( x ) lnp3 ( x )p3 ( x ) „‰Â KL – ‡ÒÒÚÓflÌË äÛÎη‡Í‡–ãÂȷ· Ë P 3 – Á‡‰‡ÌÌ˚È ÒÒ˚ÎÓ˜Ì˚È Á‡ÍÓÌ ÚÂÓËË‚ÂÓflÚÌÓÒÚÂÈ. ÇÔ‚˚ ÓÔ‰ÂÎÂ̇ ‚ Úۉ [CCL01], „‰Â P 3 ÓÁ̇˜‡ÎÓ ‡ÒÔ‰ÂÎÂÌË‚ÂÓflÚÌÓÒÚÂÈ Ó·˘Â„Ó ‡Ì„ÎËÈÒÍÓ„Ó flÁ˚͇.ê‡ÒÒÚÓflÌË ò˝ÌÌÓ̇ÑÎfl ÔÓÒÚ‡ÌÒÚ‚‡ Ò ÏÂÓÈ (Ω, , P) „‰Â ÏÌÓÊÂÒÚ‚Ó Ω ÍÓ̘ÌÓ Ë ê fl‚ÎflÂÚÒfl‚ÂÓflÚÌÓÒÚÌÓÈ ÏÂÓÈ, ˝ÌÚÓÔËfl ÙÛÌ͈ËË f : Ω → X, „‰Â ï – ÍÓ̘ÌÓ ÏÌÓÊÂÒÚ‚Ó,ÓÔ‰ÂÎflÂÚÒfl ͇ÍH( f ) =∑P( f = x ) ln( P( f = x ));x ∈XÒΉӂ‡ÚÂθÌÓ, f ÏÓÊÂÚ ‡ÒÒχÚË‚‡Ú¸Òfl Í‡Í ‡Á·ËÂÌË ÔÓÒÚ‡ÌÒÚ‚‡ Ò ÏÂÓÈ.ÑÎfl β·˚ı ‰‚Ûı Ú‡ÍËı ‡Á·ËÂÌËÈ f : Ω → X Ë g : Ω → Y Ó·ÓÁ̇˜ËÏ ˝ÌÚÓÔ˲‡Á·ËÂÌËfl (f, g): Ω → X × Y (Ó·˘Û˛ ˝ÌÚÓÔ˲) Í‡Í H(f, g) Ë ÛÒÎÓ‚ÌÛ˛ ˝ÌÚÓÔË˛Í‡Í H(f | g).
íÓ„‰‡ ‡ÒÒÚÓflÌË ò˝ÌÌÓ̇ ÏÂÊ‰Û f Ë g ÓÔ‰ÂÎflÂÚÒfl ͇Í2H ( f , g) − H ( f ) − H ( g) = H ( f | g) + H ( g | f ).É·‚‡ 14. ê‡ÒÒÚÓflÌËfl ‚ ÚÂÓËË ‚ÂÓflÚÌÓÒÚÂÈ 223чÌÌÓ ‡ÒÒÚÓflÌË fl‚ÎflÂÚÒfl ÏÂÚËÍÓÈ. äÓ΢ÂÒÚ‚Ó ËÌÙÓχˆËË ò˝ÌÌÓ̇ ÓÔ‰ÂÎflÂÚÒfl ͇ÍH ( f , g) − H ( f ) − H ( g) =∑p( f = x, g = y) ln( x, y)p( f = x, g = y).p( f = x ) p( g = y)ÖÒÎË ê – Á‡ÍÓÌ ‡‚ÌÓÏÂÌÓ„Ó ‡ÒÔ‰ÂÎÂÌËfl ‚ÂÓflÚÌÓÒÚÂÈ, ÚÓ, Í‡Í ‰Ó͇Á‡ÎÉÓÔÔ‡, ‡ÒÒÚÓflÌË ò˝ÌÌÓ̇ ÏÓÊÂÚ ·˚Ú¸ ÔÓÎÛ˜ÂÌÓ Í‡Í Ô‰ÂθÌ˚È ÒÎÛ˜‡È ÏÂÚËÍËÍÓ̘Ì˚ı ÔÓ‰„ÛÔÔ.Ç Ó·˘ÂÏ ÒÎÛ˜‡Â ÏÂÚË͇ ËÌÙÓχˆËË (ËÎË ÏÂÚË͇ ˝ÌÚÓÔËË) ÏÂÊ‰Û ‰‚ÛÏflÒÎÛ˜‡ÈÌ˚ÏË ‚Â΢Ë̇ÏË (ËÒÚÓ˜ÌË͇ÏË ËÌÙÓχˆËË) ï Ë Y ÓÔ‰ÂÎflÂÚÒfl ͇ÍH(X | Y) + H(Y | X),„‰Â ÛÒÎӂ̇fl ˝ÌÚÓÔËfl H(X | Y ) ÓÔ‰ÂÎflÂÚÒfl ͇Í∑∑p( x, y) ln p( x | y) Ëx ∈X y ∈Yp( x, y) = P( X = x | Y = y) fl‚ÎflÂÚÒfl ÛÒÎÓ‚ÌÓÈ ‚ÂÓflÚÌÓÒÚ¸˛.çÓχÎËÁËÓ‚‡Ì̇fl ÏÂÚË͇ ËÌÙÓχˆËË ÓÔ‰ÂÎflÂÚÒfl ͇ÍH ( X | Y ) − H (Y | X ).H ( X, Y )é̇ ‡‚̇ 1, ÂÒÎË X Ë Y ÌÂÁ‡‚ËÒËÏ˚ (ÒÏ.
‰Û„Ó ÔÓÌflÚË çÓχÎËÁËÓ‚‡ÌÌÓ„Ó‡ÒÒÚÓflÌËfl ËÌÙÓχˆËË, „Î. 11).åÂÚË͇ ä‡ÌÚÓӂ˘‡–å˝ÎÎÓÛÁ‡–åÓÌʇ–LJÒÒ¯ÚÂÈ̇ÑÎfl ÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ (χ, d) ÏÂÚË͇ ä‡ÌÚÓӂ˘‡–å˝ÎÎÓÛÁ‡–åÓÌʇ–LJÒÒ¯ÚÂÈ̇ ÓÔ‰ÂÎflÂÚÒfl ͇Íinf S[d(X, Y)],„‰Â ËÌÙËÏÛÏ ·ÂÂÚÒfl ÔÓ ‚ÒÂÏ ‡ÒÔ‰ÂÎÂÌËflÏ S Ô‡ (X, Y) ÒÎÛ˜‡ÈÌ˚ı ‚Â΢ËÌ X Ë Y,Ú‡ÍËı ˜ÚÓ Ï‡„Ë̇θÌ˚ÏË ‡ÒÔ‰ÂÎÂÌËflÏË X Ë Y fl‚Îfl˛ÚÒfl P1 Ë P2.ÑÎfl β·Ó„Ó ÒÂÔ‡‡·ÂθÌÓ„Ó ÏÂÚ˘ÂÒÍÓ„Ó ÔÓÒÚ‡ÌÒÚ‚‡ (χ, d) ˝ÚÓ ˝Í‚Ë‚‡ÎÂÌÚÌÓÎËÔ¯ËˆÂ‚Û ‡ÒÒÚÓflÌ˲ ÏÂÊ‰Û Ï‡ÏË supf∫fd ( P1 − P2 ), „‰Â ÒÛÔÂÏÛÏ ·ÂÂÚÒfl ÔÓ‚ÒÂÏ ÙÛÌ͈ËflÏ f Ò | f ( x ) − f ( y) | ≤ d ( x, y) ‰Îfl β·˚ı x, y ∈ χ.Ç ·ÓΠӷ˘ÂÏ ÒÏ˚ÒΠLp -‡ÒÒÚÓflÌË LJÒÒ¯ÚÂÈ̇ ‰Îfl χ = n ÓÔ‰ÂÎflÂÚÒfl ͇Í(inf S [d p ( X , Y )])1 / p ,Ë ‰Îfl p = 1 ÓÌÓ Ì‡Á˚‚‡ÂÚÒfl Ú‡ÍÊ ρ -‡ÒÒÚÓflÌËÂÏ.
ÑÎfl (χ, d) = (, | x – y |) ÓÌÓ̇Á˚‚‡ÂÚÒfl Lp-ÏÂÚËÍÓÈ ÏÂÊ‰Û ÙÛÌ͈ËflÏË ‡ÒÔ‰ÂÎÂÌËfl (CDF) Ë Â„Ó ÏÓÊÌÓÁ‡ÔËÒ‡Ú¸(inf [| X − Y | ])p1/ p= | F1 ( x ) − F2 ( x ) | p dx ∫1/ p1= | F1−1 ( x ) − F2−1 ( x ) | p dx 01/ p∫Ò Fi −1 ( x ) = sup( Pi ( X ≤ x ) < u).uëÎÛ˜‡È p = 1 ˝ÚÓÈ ÏÂÚËÍË Ì‡Á˚‚‡ÂÚÒfl ÏÂÚËÍÓÈ åÓÌʇ–ä‡ÌÚÓӂ˘‡ (ËÎË, ‚ÚÂÓËË Ù‡ÍÚ‡ÎÓ‚ ÏÂÚËÍÓÈ ï‡Ú˜ËÌÒÓ̇), ÏÂÚËÍÓÈ Ç‡ÒÒ¯ÚÂÈ̇ (ËÎËÏÂÚËÍÓÈ îÓÚ–åÛ¸Â)224ó‡ÒÚ¸ III. ê‡ÒÒÚÓflÌËfl ‚ Í·ÒÒ˘ÂÒÍÓÈ Ï‡ÚÂχÚËÍÂd -ÏÂÚË͇ é̯ÚÂÈ̇d -ÏÂÚË͇ é̯ÚÂÈ̇ ÂÒÚ¸ ÏÂÚË͇ ̇ (‰Îfl χ = n), ÓÔ‰ÂÎÂÌ̇fl ͇Í1infn n1x i ≠ yi dS, i =1∫ ∑x, y„‰Â ËÌÙËÏÛÏ ·ÂÂÚÒfl ÔÓ ‚ÒÂÏ ÒÓ‚ÏÂÒÚÌ˚Ï ‡ÒÔ‰ÂÎÂÌËflÏ S Ô‡ (X, Y) ÒÎÛ˜‡ÈÌ˚ı‚Â΢ËÌ X Ë Y, Ú‡ÍËı ˜ÚÓ Ï‡„Ë̇θÌ˚ÏË ‡ÒÔ‰ÂÎÂÌËflÏË X Ë Y fl‚Îfl˛ÚÒfl P1 Ë P2 .чÌ̇fl ÏÂÚË͇ ËÒÔÓθÁÛÂÚÒfl ‚ ÚÂÓËË ÒÚ‡ˆËÓ̇Ì˚ı ÒÎÛ˜‡ÈÌ˚ı ÔÓˆÂÒÒÓ‚,ÚÂÓËË ‰Ë̇Ï˘ÂÒÍËı ÒËÒÚÂÏ Ë ÚÂÓËË ÍÓ‰ËÓ‚‡ÌËfl.ó‡ÒÚ¸ IVêÄëëíéüçàüÇ èêàäãÄÑçéâ åÄíÖåÄíàäÖÉ·‚‡ 15ê‡ÒÒÚÓflÌËfl ‚ ÚÂÓËË „‡ÙӂɇÙÓÏ Ì‡Á˚‚‡ÂÚÒfl Ô‡‡ G = (V, E), „‰Â V – ÏÌÓÊÂÒÚ‚Ó, ̇Á˚‚‡ÂÏÓ ÏÌÓÊÂÒÚ‚ÓÏ ‚¯ËÌ „‡Ù‡ G, Ë Ö – ÏÌÓÊÂÒÚ‚Ó ÌÂÛÔÓfl‰Ó˜ÂÌÌ˚ı Ô‡ ‚¯ËÌ, ÍÓÚÓ˚Â̇Á˚‚‡˛ÚÒfl ·‡ÏË „‡Ù‡ G .
éËÂÌÚËÓ‚‡ÌÌ˚È „‡Ù (ËÎË Ó„‡Ù) ÂÒÚ¸ Ô‡‡D = (V, E), „‰Â V – ÏÌÓÊÂÒÚ‚Ó, ̇Á˚‚‡ÂÏÓ ÏÌÓÊÂÒÚ‚ÓÏ ‚¯ËÌ Ó„‡Ù‡ D, Ë Ö –ÏÌÓÊÂÒÚ‚Ó ÛÔÓfl‰Ó˜ÂÌÌ˚ı Ô‡ ‚¯ËÌ, ÍÓÚÓ˚ ̇Á˚‚‡˛ÚÒfl ‰Û„‡ÏË Ó„‡Ù‡ D.ɇÙ, Û ÍÓÚÓÓ„Ó Î˛·˚ ‰‚ ‚¯ËÌ˚ ÒÓ‰ËÌÂÌ˚ Ì ·ÓΠ˜ÂÏ Ó‰ÌËÏ Â·ÓÏ,̇Á˚‚‡ÂÚÒfl ÔÓÒÚ˚Ï „‡ÙÓÏ. ÖÒÎË ‰ÓÔÛÒ͇ÂÚÒfl ÒÓ‰ËÌÂÌË ‚¯ËÌ Í‡ÚÌ˚ÏË(Ô‡‡ÎÎÂθÌ˚ÏË) ·‡ÏË, ÚÓ Ú‡ÍÓÈ „‡Ù ̇Á˚‚‡ÂÚÒfl ÏÛθÚË„‡ÙÓÏ.