世界数学家大会(2002)卫星会议会讯

International Congress of Mathematical Software. Beijing. Aug. 1719.Contast:xgao@mmrc. iss. ac. cn; zliu@mmrc. iss. ac. ca. Wibsite: http: / /www. mathsoftware.org/Operator Algebras and Applications. Chengde. Aug.14-18.Contact: chengde@O AinChina. org; hxlin@cartan. uoregon. edu. Website: http: / /www. O AinChina. orgDifferential Geometry and Global Analysis. Tianjin. Aug.17-18.Contact: weiping@sun. nankai .edu. cnMathematical Biology Guilin. Aug.15-18.Contact: gxnu@public. glptt. …     

数学谜语

‘.，-‘.甲-鑫V-‘.，.么甲-‘.丫.血甲-主下.盛甲-五甲‘1.田. 2.安定才能团结. 3.先前太贵. (以上各打一数学名词) 4.基础不好. (打三个数学名词) 1.重心. 2.平方和. 3.近似值. 4.根、底、差数学谜语@文广!北京~~     

Coordinate Graphs

Some bars may involve many Pairs of numbers.A bar for eaeh pair would take up too mueh spaee.CoordinategraPhs are used instead.ExamPleBelow 15 a table of temPeratures for a eold January morning in Minneapolis.Put this information onto a eoordinategraPh. Time of day TemPerature(。F) 1 A.M.一2 2 A.M.一2 3 A.M.一2 4 A.M.一1 5 A.M.O 6 A.M.3 7 A.M.一1 8 A.M.O 9 A.M.3 10 A.M.7 1 1 A.M.11 12 noon 18SolutionThis eoordinate graph 15 based on two number lines.The horizontal number line r…     

多变点过程的随机控制

用鞅论方法来研究多变点过程及其随机控制已引起人们注意。P.Bremaud在这方面作了许多工作.A.F.Martins-Neto与E.Wong用鞅论方法研究了排队问题.R.Boel与 P.P.Varaiya在 1977年的一篇文章中讨论了一个较为一般的跳过程最优控制模型.M.H.A.Davis与R.J.Elliott对[3]的工作作了改进,建立了跳过程最优控制的极小值原理.R.Rishel,S.R.Pliska等人用不同的方法得到类似结果.     

数学名词谜语

1 .垂钓　　　　　 2 .客运规则　　　 3 .附则　　　　　 4.八刀　　　　　　 5 .对症下药6.我有一毛钱　 7.待命出发　 8.二牛打架　 9.五角钱一回　 1 0 .找工作1 1 .双双过磅　 1 2 .考试舞弊　 1 3 .五角钱　 1 4.五四三二一(答案在本期内找 )数学名词谜语答案1 .等于 (鱼 )　　　　 2 .乘法　　　　 3 .加法　　　　　 4.分解　　　　　 5 .开方6.余角 7.等差　　 8.对顶角　　 9.一元二次　　 1 0 .求值　　1 1 .对称 1 2 .假分数　　 1 3 .半圆　　 1 4.倒数数学名词谜语…     

IMO 1991 Problems

IMO 1991washeldinSigtuna ,Sweden .· 5 5termswererepresented .·TheodorBanicaearnedhisthirdgoldmedalforRomania .·EvgenijaMalinnikovaearnedherthirdgoldmedalfortheU .S .S .R .Sheistheonlyfemalecom petitortohaveearnedthreegoldmedals.Problem1.GivenatriangleA…     

Fuzzy Ordered Filters in Implicative Semigroups

Animplicativesemilatticeisanalgebraicsystemhavingasmodelslogicalsystemsequippedwithimplicationandconjunction,butnotpossessingadisjunction.ImplicativesemilatticeswerestudiedbyW.C.Nemitz[5].In[2],T.S.BlythgeneralizedsomeresultsofW.C.Nemitz[5]byintroducingthenotionofaBrouweriansemigroup.FollowingtheideasofNemitzandBlyth,M.W.ChanandK.P.Shum[3]introducedthenotionofnegativelypartiallyorderedimplicativesemigroupsandgeneralizedsomeresultofNemitzonimplicativesemilatticestoim-plicativesemigroups…     

PHANTOM MAPS AND SPACES OF THE SAME n-TYPE FOR ALL n

1.IntroductionLetXbeaconnectedCWcomplexandX.denoteitsn-skeleton.Amapf:X-YiscalledaphantommapifitsrestrictiontoeachskeletonXuisnullhomotopic.ItiseasytoknowthateveryphantommapfromafiniteCWcomplexortoaspacewithonlyfinitenootrivialhomotopygroupsisnecessarilytrivialuptohomotopy.HenceessentialphantommapcanoccuronlywhenthedomainXisaninfinitedimensionalspaceorthetargetisaspacewithinfinitenontrivialhomotopygroups.Suchmapsappeartobenullhomotopicfromanumberofdifferentpoilltsofview;e.g.,theyinducethe…     

PERSISTENCE OF POPULATIONS FOR A PREDATOR-PREY SYSTEM IN A POLLUTED ENVIRONMENT

1IntroductionTheinfluenceoftoxicantsonthepersistenceandextinctionofpopulationsinapollutedenvironmentisveryimportant.In1983,T.C.Hallametal.firstproposedadeterministicmodeltostudythetoxiceffectsonpopulationgrowth[fi.In1986,T.G.HallamandZ.Maproposedtheconceptofpersistenceinthemeanofpopulations[2],anewmethodtodeterminethethresholdsbetweenpersistenceandextinctionofpopulationsofnonautonomousmodelshasbeenprovidedintheirpaper.Thethresholdsbetweenpersistenceandextinctionforsomemodelshavebeenobtaine…     

POLES OF ZETA FUNCTIONS OF COMPLETE INTERSECTIONS

51.IntroductionLetF.beafinitefieldofqele~swithcharederisticp.LetXbeanThdilnensionalalgebraicsetdeadedoverF..ThezetafunctionofX/F.isdennedbywhereXOdenotesthesetofclosedpointsOfX/F.and#X(F.d)denotesthenUInberof.F.d-rationalpointsonX.ItiseasytoseethatZ(X,T)isapowerserieswithintegercoefficients.Dwork'srationalltytheoremIg]showsthatthezetafunctionZ(X,T)isrationalinT.ThuS,therearealgebraicintegerspll'.3Pr,pl,'3basuchthatThereisagoodreasonthatwemoantheabovezetafunctionbythepower(--1)"-…     

ON THE CONJECTURE OF A.LINS, W.DE MELO AND C.C.PUGH

We have proved that Lienard equation with F(x) = -F(-x) has at most n limit cycles. Under the condition, an affirmative answer to A.Lins, W.de Melo and C.C.Pugh's conjecture is given.     

Temperature dependence of S.C.L.C. in anthracene crystals

Zusammenfassung Aus der Temperaturabhängigkeit des Löcherstroms in Anthrazen-Einkristallen wird die Aktivierungsenergie bei verschiedenen Dunkelstromwerten gemessen. Die Aktivierungsenergien liegen zwischen 0,65 eV und 0,95 eV für Ströme von 10^–10 bzw. 10^–12 Ampère bei Zimmertemperatur.Ferner wird für mehrere Temperaturwerte die Aktivierung der in Haftstellen sitzenden Ladungsträger mit Hilfe von Licht verschiedener Intensität untersucht.