... harmonics. Their propertiesaredescribedinthereferencesinAppendixB.©2001 CRC Press LLC1.2.4 Prolate spheroidal coordinatesThe separated solutions of Laplace’s equation in prolate spheroidal coordi-nates ... LLCAsalreadyindicated,theboundaryconditionsmustbesupplementedbyade-cayconditionatinfinityaswellasfiniteenergyconstraintsnearedges,sothatauniqueandphysicallyrelevantsolutioncanbefound.Sinceedgesintroducedistinctivefeaturesintothetheory,letusdistinguishbetweenclosedsurfaces,thosepossessingnoboundaryoredge,andopenshells,whichhaveoneormoreboundaries.Asphericalsurfaceisclosed,whilstthehemisphericalshellisopenwithacircularboundary.Amoresophisti-cateddistinctioncanbeformulatedintopologicalterms,butthisisunneces-saryforourpurposes.Thesmoothnessofthesurface,includingthepresenceofsingularitiessuchascornersorconicaltips,isimportantinconsideringtheexistenceanduniquenessofsolutions.ThistopichasbeenextensivelyinvestigatedbyKellogg[32].However,thesurfacesunderinvestigationinthisbookareportionsofcoordinatesurfacesasdescribedintheIntroduction,andboththesurfacesandboundingcurvesareanalyticorpiecewiseanalytic.Thesmoothnessconditions,whichmustbeimposedontheclosedoropensurfacesinamoregeneralformulationofpotentialtheory,areautomaticallysatisfiedandwillbeomittedfromfurtherdiscussionexceptfortwocases,theconicalshellsconsideredinChapter6,andthetwo-dimensionalaxially-slottedcylin-dersofarbitrarycross-sectionalprofileconsideredinSection7.5;appropriatesmoothnessconditionsareconsideredintherespectivesections.Thissectionoutlinesgenericaspectsofpotentialtheoryapplicabletobothopen and closed ... the specific conditions of the problem dictate the range of parametersν, µ used in the summation or integration as appropriate.1.2.2 Cylindrical polar coordinatesApplying the method of separation...