简介:让R是一枚戒指,一,bR,(D,,并且(),并且(G,)二被概括R的推导。如果,它被证明那为所有xR的广告(x)=G(x)b,那么,下列可能性之一成立:(i)如果也orb在C被包含,那么==0并且在那里存在p,qQr(RC)以便为所有xR的D(x)=px和G(x)=qx;(ii)如果andb在C被包含,那么也=b=0或D和G线性地是C依赖;(iii)如果既不一b也没在C被包含,那么在那里存在p,qQr(RC)和wQr(R)以便(x)=[q,x]_and(x)=[x,p]_for所有xR,何处D(x)=wx?有vC和aw的xq和G(x)=xp+avx?pb=0。
简介:Thispaperpresentsacriterionfortestingtheirreducibilityofapolynomialoveranalgebraicextensionfield.Usingthiscriterionandthecharacteristicsetmethod,theauthorsgiveacriterionfortestingwhethercertaindifferenceascendingchainsarestrongirreducible,andasaconsequence,whetherthesaturationidealsoftheseascendingchainsareprimeideals.
简介:Inthispaper,rankfactorizationsandfactorleftprimefactorizationsarestudied.Theauthorsprovethatanypolynomialmatrixwithfullrowrankhasfactorleftprimefactorizations.Andforaclassofpolynomialmatrices,theauthorsgiveanalgorithmtodecidewhethertheyhaverankfactorizationsorfactorleftprimefactorizationsandcomputethesefactorizationsiftheyexist.
简介:Asignalwaveformrecoverymethodbasedonthecoprimearrayisinvestigatedtoextractthewaveformofthedesiredsignalfromspatialinterferencesinnarrowbandscenarios.Thedirectionofarrivals(DOAs)ofthedesiredsignalandinterferencesignalsareestimatedwiththecompressivesensingapproachbasedonanglegrids,andthesignalpowertogetherwiththenoisepowerareestimated.Thereafter,amodifiedsteepestdescent(SD)methodisderivedtorecoverthewaveformofthedesiredsignalandinterferencesutilizingtheestimatedpoweranddirections.Therecoveredwaveformofthedesiredsignalistheoutputoftheproposedmethod.Thesituationinwhichthesignalsarenotonthepredefinedanglegridsisalsoconsidered.TheDOAsestimatedpredefinedanglegridsisalsoconsidered.TheDOAsestimatedlikelihood(ML)angleestimation.Comparedtotheexistingbeamformingmethodsonco-primearray,theproposedmethodcanobtainthewaveformofthedesiredsignal.Simulationresultsdemonstratethattheproposedmethodcanachievegoodperformanceinsignalwaveformrecoveryandoutputsignaltonoiseratio.