简介:证明了在正则空间中闭Lindelof映射保持且逆保持submeso紧性,这改进了林寿关于正则空间完备映射保持且逆保持submeso紧性这一结果;同时我们引用一个反例说明原象空间的正则性是必要的.
简介:许多常微分方程教材关于解的整体连续依赖性的讨论都用到了一个“紧性”事实:欧氏空间中的紧集上一个局部Lipschitz函数一定在该紧集上是全局Lipschitz的.然而这一事实在教学中并非显然,不少学生在试图给出证明时都走入了一个误区.本文对这一问题从正反两方面进行了讨论.
简介:设M为S^n+1中紧致极小超曲面,Mp,n-p为Sn+1的Clifford极小超曲面,若Spec(M)=Spec(Mp,n-p)在一定条件下,我们可以得出M与Mp,n-p等距同构。
简介:证明了正则空间中闭Lindelof映射逆保持序列式meso紧性,从而改进了MancusoVJ关于正则空间中完备映射逆保持meso紧性这一结果;进一步我们指出定理条件中原象空间的正则性不可被省略而象空间的正则性可以用原象空间的正规性来替代.
简介:Inthispaper,wefirstdeterminetherelationsamongthebestboundsAandBoftheg-frame,theg-frameoperatorSandthepre-frameoperatorQandgiveanecessaryandsufficientconditionforag-framewithboundsAandBinacomplexHilbertspace.Wealsointroducethedefinitionofag-framesequenceandobtainanecessaryandsufficientconditionforag-framesequencewithboundsAandBinacomplexHilbertspace.Lastly,weconsiderthestabilityofag-framesequenceforacomplexHilbertspaceunderperturbation.
简介:X-rayimagingistheconventionalmethodfordiagnosingtheorthopedicconditionofapatient.ComputerizedTomography(CT)scanningisanotherdiagnosticmethodthatprovidespatient’s3Danatomicalinformation.However,bothmethodshavelimitationswhendiagnosingthewholeleg;X-rayimagingdoesnotprovide3Dinformation,andnormalCTscanningcannotbeperformedwithastandingposture.Obtaining3Ddataregardingthewholeleginastandingpostureisclinicallyimportantbecauseitenables3Danalysisintheweightbearingcondition.Basedontheseclinicalneeds,ahardware-basedbi-planeX-rayimagingsystemhasbeendeveloped;itusestwoorthogonalX-rayimages.However,suchmethodshavenotbeenmadeavailableingeneralclinicsbecauseofthehightcost.Therefore,weproposedawidelyadaptivemethodfor2DX-rayimageand3DCTscandata.Bythismethod,itispossibletothreedimensionallyanalyzethewholeleginstandingposture.TheoptimalpositionthatgeneratesthemostsimilarimageisthecapturedX-rayimage.Thealgorithmverifiesthesimilarityusingtheperformanceoftheproposedmethodbysimulation-basedexperiments.Then,weanalyzedtheinternal-externalrotationangleofthefemurusingrealpatientdata.Approximately10.55degreesofinternalrotationswerefoundrelativetothedefinedanterior-posteriordirection.Inthispaper,wepresentausefulregistrationmethodusingtheconventionalX-rayimageand3DCTscandatatoanalyzethewholelegintheweight-bearingcondition.
简介:A(k;g)-graphisak-regulargraphwithgirthg.A(k;g)-cageisa(k;g)-graphwiththeleastpossiblenumberofvertices.Letf(k;g)denotethenumberofverticesina(k;g)-cage.Thegirthpairofagraphgivesthelengthofashortestoddandashortestevencycle.Afc-regulargraphwithgirthpair(g,h)iscalleda(k;g,h)-graph.A(k;g,h)-cageisa(k;g,h)-graphwiththeleastpossiblenumberofvertices.Letf(k;g,h)denotethenumberofverticesina(k;g,h)-cage.Inthispaper,weprovethefollowingstrictinequalityf(k;h-1,h)
简介:In[1],ShenGuangyuconstructedseveralclassesofnewsimpleLiealgebrasofcharacteristic2,whicharecalledthevariationsofG2.Inthispaper,theauthorsinvestigatetheirderivationalgebras.ItisshownthatG2anditsvariationsallpossessuniquenondegenerateassociativeforms.TheauthorsalsofindsomenonsingularderivationsofViGfori=3,4,5,6,andtherebyconstructsomeleft-symmetricstructuresonViGfori=3,4,5,6.Someerrorsaboutthevariationsofsi(3,F)in[1]arecorrected.
简介:Thispaperprovesthat,underthehypothesisg(t,0,0)≡0andsomenaturalassumptions,thegeneratorgofabackwardstochasticdifferentialequationcanbeuniquelydeterminedbythecorrespondingg-expectationswithallterminalconditions.ThemainresultofthispaperalsoconfirmsandextendsPengShige'sconjecture.