Топология особенностей интегрируемых гамильтоновых систем с некомпактными поверхностями уровня (1105048), страница 5
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1.7: Áèôóðêàöèîííàÿ äèàãðàììà îòîáðàæåíèÿ ìîìåíòà, ïîëó÷åííàÿ ïðè ðåòðàêöèèÇäåñü îòðåçîêLòîæå óøåë íà áåñêîíå÷íîñòü, à âðåõîäå âîçíèêàåò ñëó÷àéÇàìåòèì, ÷òîE=E1èE2E2ïðè ïðåäåëüíîì ïå-(b).ìîæíî îáúåäèíèòü â îäèí ëó÷1(h, k) | k = −h; h > −4α.Îñíîâûâàÿñü íà ðåòðàêöèè, ìû îæèäàåì, ÷òî áèôóðêàöèîííàÿ äèàãðàììàáóäåò ñîñòîÿòü èç ìíîæåñòâP 1 , P2 , U , E(ñì. Ðèñóíîê 1.7)Ñíà÷àëà ìû ïåðå÷èñëèì ñëó÷àè ëèíåéíîé çàâèñèìîñòèsgrad H è sgrad K ïðèκ = 0, êîãäà ñîîòâåòñòâóþùèå êóñêè áèôóðêàöèîííîé äèàãðàììû îòîáðàæåíèÿ ìîìåíòà ÿâëÿþòñÿ ÷àñòÿìè êðèâûõ ïîðÿäêà íå âûøå 2, ïðè÷åì òî, ÷òî âýòèõ ñëó÷àÿõ êîñûå ãðàäèåíòû ëèíåéíî çàâèñèìû, áóäåò ïðîâåðåíî íåïîñðåäñòâåííî. Çàòåì áóäåò ïîêàçàíî, ÷òî âñå âîçìîæíîñòè, êîãäà êîñûå ãðàäèåíòûëèíåéíî çàâèñèìû, ñâîäÿòñÿ ê ýòèì èëè æå ïðèâîäÿò ê òî÷êå1)S1 = S3 = 0.Îòñþäà ñëåäóåò, ÷òî(0, 0).Q2 = S3 R1 − S1 R3 = 0.Ïðè ýòîììàòðèöà, ñîñòàâëåííàÿ èç êîñûõ ãðàäèåíòîâ, ïðèîáðåòàåò ñëåäóþùèé âèä:39Î÷åâèäíî, ÷òî0Q10S2 A0−2αS2 Q10 Q1 B 0 S2 AB 0 −2αS2 Q1 Bsgrad Hè.sgrad K â ýòîì ñëó÷àå ëèíåéíî çàâèñèìû, òàê êàêîíè ïðîñòî ïðîïîðöèîíàëüíû ñ êîýôôèöèåíòîì ïðîïîðöèîíàëüíîñòè, ðàâíûìB.Ëåãêî ïðîâåðèòü, ÷òî çàâèñèìîñòühèkíà äàííîì êóñêå áèôóðêàöèîííîéäèàãðàììû âûðàæàåòñÿ ñëåäóþùèì îáðàçîì:k=κ 2h − h + αg 2 .α(1.4.1)Íàéäåì òåïåðü êðèòè÷åñêèå òî÷êè è îáëàñòü èçìåíåíèÿh.Ðàññìîòðèìñëåäóþùóþ ñèñòåìó, çàäàþùóþ êðèòè÷åñêèå òî÷êè:S2 R2 = g,αS22 − S2 R1 = h,(1.4.2) κS 2 + R2 + R2 + R2 = 1.2123Îíà èìååò ðåøåíèå ïðè ôèêñèðîâàííîìS2â òîì è òîëüêî òîì ñëó÷àå,êîãäàg 2 (h − αS22 )2+6 1 − κS22 .22S2S2(1.4.3) ñëó÷àå ñòðîãîãî íåðàâåíñòâà èìååì 2 òî÷êè è 1 òî÷êó â ïðîîáðàçå ïðèïðîåêöèè êðèòè÷åñêèõ òî÷åê íà (1.4.3) â ñëó÷àå ðàâåíñòâà.Îáîçíà÷èìS22÷åðåçy.Òîãäà íåðàâåíñòâî (1.4.3) ïåðåïèøåòñÿ ñëåäóþùèìîáðàçîì:40(α2 + κ)y 2 − (2αh + 1)y + g 2 + h2 6 0.(1.4.4)Íåðàâåíñòâî (1.4.4) èìååò íåîòðèöàòåëüíûå ðåøåíèÿ òîãäà è òîëüêî òîãäà,êîãäà D = (2αh + 1)2 − 4(α2 + κ)(g 2 + h2 ) > 0,Çäåñü ìû ó÷ëè, ÷òî(1.4.5)2αh + 1 > 0.α2 + κ > 0â íàøåì ñëó÷àå (ïðèκ = 0).Èç ñèñòåìû íåðàâåíñòâ (1.4.5) ñëåäóåò, ÷òî îáëàñòü èçìåíåíèÿh ïðè κ = 0èìååò âèä:h>4α2 g 2 − 1.4α(1.4.6)Çàìåòèì, ÷òî ìû ïîëó÷èëè ðîâíî òî æå, ÷òî è ïðè ðåòðàêöèè ñso(4)? .Òàêèì îáðàçîì, ñîîòâåòñòâóþùèé êóñîê áèôóðêàöèîííîé äèàãðàììû çàäàåòñÿ ñèñòåìîé(1.4.1),(1.4.6).
×òîáû ïîíÿòü, ÷òî æå ïðåäñòàâëÿþò ñîáîéêðèòè÷åñêèå òî÷êè, çàìåòèì, ÷òî íóæíî ñêëåèòü 2 ýêçåìïëÿðà îäíîìåðíûõS,ìíîãîîáðàçèé(1.4.3), îòâå÷àþùèõ âñåâîçìîæíûìâ íåðàâåíñòâå(1.4.3) èìååò ìåñòî ðàâåíñòâî). Ëåãêî âèäåòü, ÷òî â íàøåìñëó÷àå ìíîæåñòâî òî÷åê èçïî ãðàíèöå (òàì, ãäå(1.4.3) ÿâëÿåòñÿ îáúåäèíåíèåì äâóõ îòðåçêîâ.Ïîñêîëüêó ïðè ñêëåéêå äâóõ îòðåçêîâ ïî èõ ãðàíèöå (ïî äâóì òî÷êàì) ïîëó÷àåòñÿ îêðóæíîñòü, òî ìû ïîëó÷àåì, ÷òî êðèòè÷åñêèå òî÷êè îáðàçóþò 2îêðóæíîñòè (ñì. Ðèñóíîê 1.8).Ðèñ. 1.8: Ñêëåéêà äâóõ îòðåçêîâ412)S2 = S3 = 0.Îòñþäà ñëåäóåò, ÷òîQ1 = S2 R3 − S3 R2 = 0.Ìàòðèöàêîñûõ ãðàäèåíòîâ ïåðåïèøåòñÿ ñëåäóþùèì îáðàçîì:κ−2 S1 Q2 −Q2 0 0 0 S1 Bα.κQ2 A 0 0 0 −S1 BA 2 S1 Q2 AαÏðè ýòîìhkíà ýòîì êóñêå áèôóðêàöèîííîé äèàãðàììû âûðàæàåòñÿ ÷åðåçñëåäóþùèì îáðàçîì:k = −αh2 − h −κ 2g .α(1.4.7)Àíàëîãè÷íî ïåðâîìó ïóíêòó ïîëó÷àåì ñëåäóþùóþ ñèñòåìó:S1 R1 = g,κ− S12 + S1 R2 = h,α(1.4.8) κS 2 + R2 + R2 + R2 = 1.1123Îíà èìååò ðåøåíèå ïðè ôèêñèðîâàííîìS1òîãäà è òîëüêî òîãäà, êîãäàg 2 (h + κα S12 )2+6 1 − κS12 .22S1S1Îáîçíà÷èìS12÷åðåçx.(1.4.9)Íóæíî, ÷òîáû ñëåäóþùåå íåðàâåíñòâî èìåëî íåîòðè-öàòåëüíûå ðåøåíèÿ:α2 + κ 22κh−κx+(1−)x − (g 2 + h2 ) > 0.2ααÏðèκ=0(1.4.10)èìååì:S12 − (g 2 + h2 ) > 0.Îíî èìååò ðåøåíèå ïðè ëþáîìh ∈ R.(1.4.11)Ýòî çíà÷èò, ÷òî ìû èìååì 2 êðèòè-÷åñêèå ïðÿìûå.Òîò æå ðåçóëüòàò áûë ïîëó÷åí è ïðè ðåòðàêöèè (ïðè42κ → +0).3)Q1 = 0, A = 2αQ3 − q = 0. ýòîì ñëó÷àåsgrad K = 0.1(1 − 4κg 2 )4α1Ïðè κ = 0 èìååì: q = −1, îòêóäà Q3 = −.
Îòñþäà ïîëó÷àåì ñèñòåìó:2α Q22 + Q23 = S12 + S22 + S32 − g 2 ,1S 2 Q2 −S3 = 0.2αÂûÿñíèì, â êàêèõ ïðåäåëàõ ìåíÿåòñÿ h.11, îòêóäà h > −.h = αS22 + Q3 = αS22 −2α2α122222Äàëåå S3 = 2αS2 Q2 . Èç ïåðâîãî óðàâíåíèÿ: Q2 +4α2 = S1 + S2 + S3 − g .Q22 + 4α1 2 + g 2 − S12Q22 + 4α1 2 + g 24g 2 α212Îòñþäà S2 =(1 +6=) 61 + 4α2 Q221 + 4α2 Q224α21 + 4α2 Q221 + 4g 2 α24α2k=Î÷åâèäíî, ÷òî ýòè çíà÷åíèÿ äîñòèãàþòñÿ, òàê æå, êàê è âñå ïðîìåæóòî÷-2íûå.
Ýòî çíà÷èò, ÷òî S2h∈ 0;1+4g 2 α24α2i. Îòñþäàh∈h1 4α2 g 2 −1− 2α; 4α2i.Çàìåòèì, ÷òî ýòî íå ñîâñåì òî, ÷òî ïîëó÷èëîñü ïðè ðåòðàêöèè. Òàì áûëî1. Îáúÿñíÿåòñÿ ýòî ñëåäóþùèì îáðàçîì. Ãîðèçîíòàëüíûé2ακ 22îòðåçîê U â ñëó÷àå so(4) øåë îò âåðøèíû ïàðàáîëû k = −αh − h −g , íàακ 2ïðàâëåííîé âåòâÿìè âíèç, äî äàëüíåé òî÷êè ïåðåñå÷åíèÿ ñ ïàðàáîëîéh −αh + αg 2 , íàïðàâëåííîé âåòâÿìè ââåðõ. Ïðè ïðåäåëüíîì ïåðåõîäå âòîðàÿ ïàðàk = −h, h > −áîëà âûðîæäàåòñÿ â ëó÷k = −h + αg 2 .
Ïðè ýòîì äàëüíÿÿ òî÷êà ïåðåñå÷åíèÿãîðèçîíòàëüíîãî îòðåçêà ñ íåé óõîäèò íà áåñêîíå÷íîñòü, à áëèæíÿÿ òî÷êà êàê4α2 g 2 − 1. Ïîýòîìó òî, ÷òî ìû4α14α2 g 2 − 1−6h6.2α4αðàç ñòðåìèòñÿ êîòðåçîê43ïîëó÷èëè íå ëó÷h>−1, à2αÂûÿñíèì, êàêîå ìíîãîîáðàçèå îáðàçóþò êðèòè÷åñêèå òî÷êè. Ïðèìîæíî âûáðàòüíîìS2äëÿS1èS21h > − 2αäâóìÿ ñïîñîáàìè: ñî çíàêîì + è ñî çíàêîì -. Ïðè âûáðàí-Q2èìååì ñëåäóþùåå ñîîòíîøåíèå:S12 + (4α2 S22 − 1)Q22 = g 2 +1− S22 .24α4α2 S22 − 1 = 4αh + 1. Çàìåòèì, ÷òî ïðàâàÿ ÷àñòü âñåãäà íåîòðèöàòåëüíà:4αh + 14α2 g 2 − 1g 2 + 4α1 2 − S22 = g 2 −>0, ò.ê.
h 6.4α24αÏðè 4αh + 1 > 0 ýòî ñîîòíîøåíèå çàäàåò ýëëèïñ, òîïîëîãè÷åñêè îêðóæíîñòü, à ïðè4αh + 1 < 0âîçìîæíîñòè âûáîðàïðè1h > − 4α4)S2 ãèïåðáîëó, òîïîëîãè÷åñêè2ïðÿìûå. Ñ ó÷åòîìäâóìÿ ñïîñîáàìè ïîëó÷àåì, ÷òî êðèòè÷åñêèå òî÷êèîáðàçóþò 2 îêðóæíîñòè, à ïðè1h < − 4α 4 ïðÿìûå.κQ2 = 0, B = q + 2 Q3 = 0.αα(1 − 4κg 2 )4κïðè κ = 0.k=−Ýòî ðåøåíèå íå ñóùåñòâóåò5)(2αS2 S3 − Q2 )Q1 = S1 S2 A,S1 S2 + Q1 Q2 = 0,Q1 Q2 6= 0.Ïåðåïèñûâàåì ïåðâîå óðàâíåíèå ñ ó÷åòîì âòîðîãî:2α(S2 S3 Q1 − S1 S2 Q3 ) = 0,S1 S2 + Q1 Q2 = 0Q1 Q2 6= 0.Ïåðâîå óðàâíåíèå ìîæíî ïîäåëèòü íàóðàâíåíèÿQ1 = 0èëèQ2 = 0).44S2 , òàê êàê S2 6= 0 (èíà÷å èç âòîðîãîÎêîí÷àòåëüíî ïîëó÷àåì:S3 Q1 − S1 Q3 = 0,S1 S2 + Q1 Q2 = 0Q1 Q2 6= 0.Âûðàæàÿ èç ïåðâîãî óðàâíåíèÿäåñòâîhS, Qi = 0,S3 ,èç âòîðîãî Q2è ïîäñòàâëÿÿ â òîæ-ïîëó÷àåì:S22 = Q21 + Q23 .Îòñþäàk = −hè(1.4.12)1h > − 4α.Èç ïåðâîãî óðàâíåíèÿS12 S22 = Q21 Q22 .Ïîäñòàâëÿåì â íåãîS12 (Q21 + Q23 ) = Q21 Q22 .Äàëåå èç âòîðîãî óðàâíåíèÿQ1 6= 0,S12 Q23 = S32 Q21 .S22 = Q21 + Q23 :(1.4.13)Ïîäñòàâëÿåì ýòî â (1.4.13):Q21 (S12 + S32 − Q22 ) = 0.(1.4.14)Q22 = S12 + S32 .(1.4.15)çíà÷èò,S 2 = Q2 − g 2 .
Ïîäñòàâëÿÿ â íåãî (1.4.12) è1(1.4.15), ìû ïîëó÷èì g = 0. Ïðè ýòîì k = −h, h > −. Ðîâíî òî æå ñàìîå4αïîëó÷àåòñÿ ïðè ïîäñòàíîâêå g = 0 è ñëó÷àå (1), òî åñòü íè÷åãî íîâîãî ýòîòÒåïåðü âîñïîëüçóåìñÿ òîæäåñòâîìñëó÷àé íàì íå äàåò.6) Òåïåðü äîêàæåì, ÷òî ìû ïåðå÷èñëèëè âñå íåòðèâèàëüíûå ñëó÷àè, êîãäàêîñûå ãðàäèåíòûHèK ëèíåéíî çàâèñèìû.
Îñòàëüíûå (òðèâèàëüíûå) ñëó÷àè45ëèíåéíîé çàâèñèìîñòè ïðèâîäÿò ê òî÷êå2×6ìàòðèöûÏðèðàâíÿâñëåäóåò, ÷òîsgrad H(0, 0).∆ijÎáîçíà÷èì ÷åðåçìèíîðû.sgrad Kìèíîðû ∆13è∆23ê íóëþ, ïîëó÷àåì ñëåäóþùåå: èçQ2 [(2αS2 S3 − Q2 )Q1 − S1 S2 A] = 0,à èç∆13 = 0∆23 = 0ïîëó÷àåì, ÷òîQ2ðàâíî 0, ëèáîQ1 (S1 S2 + Q1 Q2 ) = 0.Ìû ïîëó÷èëè ñëåäóþùóþ àëüòåðíàòèâó: ëèáîQ1èëèQ1âûïîëíåíî 5). Ðàçáåðåìñÿ òåïåðü ñ òåì, ÷òî ïðîèñõîäèò, êîãäàðàâíîI.Q20.Q1 = 0, A 6= 0S1 S2 = 01)èëèQ1 = 0, A = 0(ñëó÷àéðàçîáðàí â 3). Èçñëåäóåò, ÷òîÐàññìîòðèì ðàçëè÷íûå ñëó÷àè:S1 = 0, S3 6= 0 (S1 = S3 = 02αS2 S3 − Q2= αQ2 A1ñîîòâåòñòâóåò ñëó÷àþñëó÷àå íåíóëåâûì ìîæåò áûòü òîëüêî ìèíîð∆14∆34â òåîðåìå).  ýòîì∆14 . Q3 = −S2 R1 , Q2 = S3 R1 .S2 A = −S2 A(2αS2 S3 − Q2 + Q2 A) =−S2 A= −S2 A (2αS2 S3 − Q2 + Q2 (2αQ3 + 1)) = −2αS2 A(S2 S3 + Q2 Q3 ).Ïî óñëîâèþ,A 6= 0,çíà÷èò, ëèáîa)S2 = 0,b)S2 S3 + Q2 Q3 = 0.òîãäà−S2 R1 , Q2 = S3 R1 ,R12 ).
S3 6= 0,R3 = 0.2)Q3 = 0S2 S3 + Q2 Q3 = 0.h = k = 0.S2 = 0g = 0,è(S, R). Q3 =S1 = 0. S2 S3 + Q2 Q3 = S2 S3 − S2 S3 R12 = S2 S3 (1 −ðàçîáðàí â ï. (a), ïîýòîìók = −h,S2 = 0, S3 6= 0 (S2 = S3 = 0Èç òîæäåñòâàëèáîÇäåñü óäîáíåå âåðíóòüñÿ ê ïåðåìåííûìòàê êàêñëó÷àéÏðè ýòîìèS2 = 0,R12 = 1,òî åñòü ìû ïîëó÷àåì ñëó÷àéñîîòâåòñòâóþò ñëó÷àþS1 Q1 + S2 Q2 + S3 Q3 = 046è óñëîâèÿ2îòêóäà5R2 =â òåîðåìå.â òåîðåìå)S3 6= 0ñëåäóåò, ÷òîQ3 = 0.II.Ïîëó÷àåì, ÷òîQ2 = 0.Èçh = k = 0.∆23 = 0S1 S2 Q1 = 0.ïîëó÷àåì, ÷òîÏîñëåäîâàòåëüíîðàññìîòðèì ðÿä ñëó÷àåâ.1)Q1 = 0.
∆34 = 2αS1 S22 A.Q1 = A = 02)óæå ðàçîáðàíû âûøå.S2 = 0. ∆25 = 2αQ1 (S1 Q3 − S3 Q1 ).ðàçîáðàí âûøå), ïîýòîìóòàê êàê(S12 + S32 )R2 .ëèáîËèáîR2 = 0,Q1 6= 0(ñëó÷àéQ1 = S2 = 0Ïåðåéäåì ê ïåðåìåííûì(S, R).S2 = 0. S1 Q3 − S3 Q1 = S12 R2 + S32 R2 =S = 0.S1 = 0, ∆12 = −2αS2 S3 Q1S3 = 0ÍîS1 Q3 − S3 Q1 = 0.Q1 = −S3 R2 , Q3 = S1 R2 ,3)Q1 = S1 = 0, Q1 = S2 = 0,Íî ñëó÷àè îáîèõ ñëó÷àÿõh = k = 0.äîëæåí áûòü ðàâåí íóëþ. Íî ñëó÷àéS1 =Q1 = S1 = 0 Q2 = S2 = 0áûëèñîîòâåòñòâóåò ï. 1 òåîðåìû, à ñëó÷àèðàçîáðàíû âûøå.Ñëó÷àé áèôóðêàöèîííûõ íåêðèòè÷åñêèõ òî÷åê áóäåò ðàçîáðàí íèæå â ïàðàãðàôå 1.7.Èòàê, íàìè äîêàçàíà ñëåäóþùàÿÒåîðåìà 5.4Ðàññìîòðèì M1,g, g ∈ R.
ÒîãäàÏðè κ = 0 áèôóðêàöèîííàÿ äèàãðàììà îòîáðàæåíèÿ ìîìåíòà ñîñòîèòèç ñëåäóþùèõ êðèâûõ:4α2 g 2 − 11) ëó÷à k = −h + αg , h >,4αïðè ýòîì â ïðîîáðàçå ïîëó÷àþòñÿ 2 êðèòè÷åñêèå îêðóæíîñòè;22) ïàðàáîëû k = −αh2 − h, h ∈ R,ïðè ýòîì â ïðîîáðàçå 2 êðèòè÷åñêèå ïðÿìûå;114α2 g 2 − 13) îòðåçêà k =,−6h6,4α2α4α11ïðè h < −â ïðîîáðàçå áóäóò 4 êðèòè÷åñêèå ïðÿìûå, à ïðè h > −4α4α47Ðèñ.
1.9: Áèôóðêàöèîííàÿ äèàãðàììà îòîáðàæåíèÿ ìîìåíòà 2 êðèòè÷åñêèå îêðóæíîñòè;14) ëó÷à k = −h, h > − .4αÏðè÷åì òèïû (1 − 3) ÿâëÿþòñÿ êðèòè÷åñêèìè çíà÷åíèÿìè, à òèï 4 íåêðèòè÷åñêèìè áèôóðêàöèîííûìè çíà÷åíèÿìè.Çàìå÷àíèå 5.Ïðè κ = 0 áèôóðêàöèîííàÿ äèàãðàììà îòîáðàæåíèÿ ìî-ìåíòà ñîâïàäàåò ñ ïåðåñå÷åíèåì áèôóðêàöèîííîé äèàãðàììû, ïîëó÷åííîé ñïîìîùüþ ðåòðàêöèè c so(4), ñ îáðàçîì îòîáðàæåíèÿ ìîìåíòà.Íà Ðèñóíêå 1.9 èçîáðàæåíà áèôóðêàöèîííàÿ äèàãðàììà îòîáðàæåíèÿ ìîìåíòà.
Ïðè ýòîì ñïëîøíûìè ëèíèÿìè ïîêàçàíû êðèòè÷åñêèå çíà÷åíèÿ, àïóíêòèðíîé ëèíèåé íåêðèòè÷åñêèå áèôóðêàöèîííûå çíà÷åíèÿ.1.5Èíäåêñû êðèòè÷åñêèõ òî÷åêÁóäåì ïî-ïðåæíåìó ðàáîòàòü â êîîðäèíàòàõ4M1,gg2.ÿâëÿåòñÿ ïîâåðõíîñòüþ óðîâíÿ ôóíêöèéÂåêòîðûgrad H , grad f1 , grad f2(S, Q). ýòèõ êîîðäèíàòàõf1 = hS, Qi = 0, f2 = S 2 − Q2 =èìåþò ñëåäóþùèé âèä:48grad H = (0, 2αS2 , 0, 0, 0, 1),grad f1 = (Q1 , Q2 , Q3 , S1 , S2 , S3 ),grad f2 = (2S1 , 2S2 , 2S3 , −2Q1 , −2Q2 , −2Q3 ).Ìàòðèöû âòîðûõ ÷àñòíûõ ïðîèçâîäíûõGK , GHèGf2èìåþò ñëåäóþùèé âèä:0 00 00 0GK = 0 00 00 0000GH = 0000000000000 −2α 000000000 0 02α 0 0 000 0 000 0 000 0 000 0 0490 0 0 ,0 0 −2α000,000ôóíêöèéK, Hèf2200Gf2 = 0000 00002 0 0 0 00 2 0 0 0.0 0 −2 0 0 0 0 0 −2 0 0 0 0 0 −2Äëÿ âû÷èñëåíèÿ èíäåêñîâ êðèòè÷åñêèõ òî÷åê íóæíî ñäåëàòü ñëåäóþùåå:1. Íàõîäèì çàâèñèìîñòüòî÷êå.
Ïóñòügrad K , grad H , grad f1ègrad f2â êðèòè÷åñêîégrad K = A(S, Q)grad H + B(S, Q)grad f1 + C(S, Q)grad f2 .2. Ñîñòàâëÿåì ìàòðèöó3. Íàõîäèì áàçèñG = GK − A(S, Q)GH − B(S, Q)Gf1 − C(S, Q)Gf2 .e1 , e2 , e3â êàñàòåëüíîì ïðîñòðàíñòâå â êðèòè÷åñêîé òî÷-3ëèíåéíî íåçàâèñèìûõ âåêòîðà, îðòîãîíàëüíûõêå. Äëÿ ýòîãî íàäî íàéòèâåêòîðàìgrad H , grad f1åìëþùåìR6 .ègrad f24. Âû÷èñëÿåì ìàòðèöó ôîðìûñòâî, íàòÿíóòîå íàâ ñìûñëå ñêàëÿðíîãî ïðîèçâåäåíèÿ â îáú-G̃ îãðàíè÷åíèÿ ôîðìûGíà ïðîñòðàí-e1 , e2 , e3 .5. Îäíèì èç ñîáñòâåííûõ çíà÷åíèé ìàòðèöûG̃ áóäåò 0. Íóæíî íàéòè çíà-êè äâóõ äðóãèõ ñîáñòâåííûõ çíà÷åíèé ìàòðèöûG̃.×èñëî åå îòðèöàòåëüíûõñîáñòâåííûõ çíà÷åíèé è áóäåò èíäåêñîì êðèòè÷åñêîé òî÷êè.6.