The1989SeminaronStochasticProcesseswasheldattheUniversityof CaliforniaatSanDiegoonMarch30,31andApril1,Hl89. Thiswastheninth inanannualseriesofmeetingswhichprovideresearcherswiththeopportunity todiscusscurrentworkonstochasticprocessesinaninformalandenjoyableat- mosphere. PreviousseminarswereheldatPrincetonUniversity,Northwestern University,theUniversityofFloridaandtheUniversityofVirginia. Theseminar hasgrownovertheyears,withatotalofseventy-fiveparticipantsin1989. Fol- lowingthesuccessfulformatofpreviousyears,therewerefiveinvitedlectures, deliveredby K. L. Chung,D. Dawson, R. Durrett,N. IkedaandT. Lyons,with theremainderoftimebeingdevotedtostructured,butlessformal,discussionson currentworkandproblems. Severalsmallergroupsalsoheldworkshopsessions onspecifictopicssuchas:mper-processes,diffusionsonfractalsandHarnack inequalities. Theparticipant. s'interestandenthusiasmcreatedalivelyandstim- ulatingcnvironmentfortheseminar. Asampleoftheresearchdiscussedthereis containedinthisvolume. Thc1989SeminarwasmadepossiblebythesupportoftheNationalScience Foundation,theNationalSecurityAgencyandtheUniversityofCaliforniaatSan Diego.\Yeextendourthankstothem,andtothepublishcrBirkhauserBoston, fortheirsupportandencouragemcnt. Finally,thanksgotoLynn\,yilliamsforher cheerfulassistancewiththeseminarorganizationandproductionofthisvolume. P. J. Fitzsimmons R. J. Williams LaJolla,1989 LISTOFPARTICIPANTS P. Arzberger M. Emery E. Perkins J. Pitman B. Atkinson S. N. Evans L. Pitt J. Azema N. Falkner M. Bachman P. Fitzsimmons A. O. Pittenger Z. Pop-Stojanovic M. Barlow R. K. Getoor R. Bass J. Glover S. Port C. Bezuidenhout H. Heyer P. Protter R. Blumenthal K. Hoffmann K. M. Rao G. Brosamler J. Horowitz J. Rosen C. Burdzy P. Hsu T. Salisbury D. Burkholder N. Ikeda M. J. Sharpe H. Cai O. Kallenberg C. T. Shih R. Carmona F. Knight A. Sznitman W. Chen-Masters Y. Kwon M. Taksar K. L. Chung T. Kurtz L. Taylor E. Cinlar T. Liggett S. J. Taylor M. Cranston T. Lyons G. Terdik R. Dalang P. March E. Toby R. DanteDeBlassie M. Marcus R. Tribe R. Darling P. McGill J. Walsh D. Dawson T. Mountford J. Watkins J. Deuschel B. Oksendal S. Weinryb N. Dinculeanu V. Papanicolaou R. Williams R. Durrett R. Pemantle Z. Zhao E. B. Dynkin M. Penrose W. Zheng TABLEOFCONTENTS R. F. BASS Aprobabilisticproofoftheboundary 1 and K.BURDZY Harnackprinciple J. -D. DEUSCHEL LogarithmicSobolevinequalitiesof 17 symmetricdiffusions S. N. EVANS RescalingthevacancyofaBoolean coverageprocess 23 TheBlumenthal-Getoor-McKean P. J. FITZSIMMONS, R. K. GETOOR Theoremrevisited 35 andM. J. SHARPE P. J. FITZSIMMONS Localtimes,occupationtimes,andthe Lebesguemeasureoftherangeofa andS. C.