TeodorBulboacǎ,SantoshB.Joshi,andPranayGoswami ComplexAnalysis Also of Interest ComplexAnalysis. AFunctionalAnalyticApproach FriedrichHaslinger,2017 ISBN978-3-11-041723-4,e-ISBN(PDF)978-3-11-041724-1, e-ISBN(EPUB)978-3-11-042615-1 ElementaryFunctionalAnalysis MaratV.Markin,2018 ISBN978-3-11-061391-9,e-ISBN(PDF)978-3-11-061403-9, e-ISBN(EPUB)978-3-11-061409-1 RealAnalysis. MeasureandIntegration MaratV.Markin,2019 ISBN978-3-11-060097-1,e-ISBN(PDF)978-3-11-060099-5, e-ISBN(EPUB)978-3-11-059882-7 AppliedNonlinearFunctionalAnalysis. AnIntroduction NikolaosS.Papageorgiou,PatrickWinkert,2018 ISBN978-3-11-051622-7,e-ISBN(PDF)978-3-11-053298-2, e-ISBN(EPUB)978-3-11-053183-1 FunctionalAnalysis. ATerseIntroduction GerardoChacón,HumbertoRafeiro,JuanCamiloVallejo,2016 ISBN978-3-11-044191-8,e-ISBN(PDF)978-3-11-044192-5, e-ISBN(EPUB)978-3-11-043364-7 Teodor Bulboacǎ, Santosh B. Joshi, and Pranay Goswami Complex Analysis | Theory and Applications MathematicsSubjectClassification2010 30-XX Authors Prof.Dr.Habil.TeodorBulboacǎ Babeş-BolyaiUniversity FacultyofMathematicsandComputerScience Str.MihailKogălniceanuNr.1 400084Cluj-Napoca Romania [email protected] Prof.Dr.SantoshB.Joshi WalchandCollegeofEngineering DepartmentofMathematics 416415Maharastra India [email protected] Prof.Dr.PranayGoswami AmbedkarUniversityDelhi KashmereGateCampus LothianRoad,KashmereGate 110006Delhi India [email protected] ISBN978-3-11-065782-1 e-ISBN(PDF)978-3-11-065786-9 e-ISBN(EPUB)978-3-11-065803-3 LibraryofCongressControlNumber:2019938423 BibliographicinformationpublishedbytheDeutscheNationalbibliothek TheDeutscheNationalbibliothekliststhispublicationintheDeutscheNationalbibliografie; detailedbibliographicdataareavailableontheInternetathttp://dnb.dnb.de. ©2019WalterdeGruyterGmbH,Berlin/Boston Coverimage:Lokal_Profil(Grafic»conformal_grid«)–MichaelBernhart(surface) Typesetting:VTeXUAB,Lithuania Printingandbinding:CPIbooksGmbH,Leck www.degruyter.com Contents Preface|XI 1 Complexnumbers|1 1.1 Thefieldofthecomplexnumbers|1 1.2 Thecomplexplane|3 1.3 Thetopologicalandmetricstructureofthecomplexplane|6 1.3.1 Basicdefinitionsandnotation|6 1.4 Complexfunction,limits,continuity|9 1.5 Thecompactifiedcomplexplane|10 1.5.1 Thegeometricinterpretationoftheφfunction|12 ℂ̂ 1.5.2 Thetopologicalstructureof |12 1.6 Exercises|14 2 Holomorphicfunctions|17 2.1 Thederivativeoftherealvaluedcomplexfunctions|17 2.2 Thedifferentiabilityofacomplexfunction|19 2.3 Thederivativeofacomplexfunction|23 2.3.1 Thepropertiesofthederivative|25 2.4 Thegeometricinterpretationofthederivative|29 2.5 Entirefunctions|33 2.5.1 Thepolynomialfunction|33 2.5.2 Theexponentialfunction|33 2.5.3 Complextrigonometricfunctions|34 2.5.4 Complexhyperbolicfunctions|35 2.6 Bilineartransforms|35 2.6.1 Decompositionsinelementaryfunctions|36 2.7 TheMöbius-typegroups|39 2.8 Multivaluedfunctions|43 2.8.1 Thelogarithmicfunction|43 2.8.2 Inversetrigonometricfunctions|45 2.8.3 Thepowerfunction|46 2.9 Exercises|47 2.9.1 Realvariablecomplexfunctions|47 2.9.2 Thederivativeofacomplexfunction|47 2.9.3 Entirefunctions|49 2.9.4 Bilineartransforms|49 3 Thecomplexintegration|51 VI | Contents 3.1 Thehomotopictheoryofthepaths|51 3.1.1 Simplyconnecteddomains|55 3.1.2 Functionsofboundedvariationandpaths|58 3.2 Thecomplexintegral|60 3.2.1 TheRiemann–Stieltjesintegralforcomplexvaluedfunctions|60 3.3 TheCauchytheorem|66 3.3.1 Theconnectionbetweentheintegralandtheprimitivefunction|66 3.3.2 TheCauchytheorem|74 3.4 TheCauchyformulaforthedisc|79 3.5 Theanalyticalbranchesofmultivaluedfunctions|82 3.6 Theindexofapath(curve)withrespecttoapoint|84 3.7 Cauchyformulaforclosedcurves|87 3.8 SomeconsequencesofCauchyformula|88 3.9 SchwarzandPoissonformulas|91 3.10 Exercises|94 3.10.1 Thecomplexintegral|94 3.10.2 TheCauchytheorem|96 3.10.3 TheCauchyformulaforthedisc|97 3.10.4 SomeconsequencesofCauchyformula|101 3.10.5 Multivaluedfunctionsanalyticalbranches|102 4 Sequencesandseriesofholomorphicfunctions|105 4.1 Sequencesofholomorphicfunctions|105 4.2 Seriesoffunctions|107 4.3 Powerseries|108 4.4 Theanalyticityofholomorphicfunctions|111 4.5 Thezerosofholomorphicfunctions|114 4.6 Themaximumprincipleoftheholomorphicfunctions|117 4.7 Laurentseries|122 4.8 Isolatedsingularpoints|127 4.9 Meromorphicfunctions|131 4.10 Exercises|134 4.10.1 Powerseries|134 4.10.2 TaylorandLaurentseries|135 4.10.3 Isolatedsingularpoints|138 4.10.4 Themodulemaximumoftheholomorphicfunctions|139 5 Residuetheory|141 5.1 Residuetheorem|141 5.2 Applicationsoftheresiduetheoremtothecalculationofthe integrals|144 5.3 Thestudyofmeromorphicfunctionswiththeresiduetheorem|158 Contents | VII 5.4 Exercises|165 5.4.1 Residuetheorem|165 5.4.2 Applicationsoftheresiduetheoremtothecalculationofthe trigonometricintegrals|168 5.4.3 Applicationsoftheresiduetheoremtothecalculationoftheimproper integrals|169 5.4.4 Thestudyofmeromorphicfunctionsusingtheresiduetheorem|169 6 Conformalrepresentations|171 6.1 Specialclassesofholomorphicfunctions|171 6.2 Univalentfunctions|175 6.3 Theproblemofconformalrepresentation|179 6.4 TheRiemannmappingtheorem|181 6.5 Exercises|187 7 Solutionstothechapterwiseexercises|191 7.1 SolutionstotheexercisesofChapter1|191 7.2 SolutionstotheexercisesofChapter2|199 7.3 SolutionstotheexercisesofChapter3|218 7.4 SolutionstotheexercisesofChapter4|277 7.5 SolutionstotheexercisesofChapter5|322 7.6 SolutionstotheexercisesofChapter6|380 Bibliography|405 Index|407 | DedicatedtothememoryofProfessorPetruT.Mocanu(1931–2016)