Mathematical Sciences: Recursion Theory
{'Code': '03040200', 'Directorate': {'Abbreviation': 'MPS', 'LongName': 'Direct For Mathematical & Physical Scien'}, 'Division': {'Abbreviation': 'DMS', 'LongName': 'Division Of Mathematical Sciences'}}
{'SignBlockName': 'Ralph M. Krause', 'PO_EMAI': None, 'PO_PHON': None}
Lempp will pursue research in recursion theory.  The main               project is to study the decidability of fragments of the first-                 order theories of the sets of r.e. degrees and of Turing degrees                where information about the jump operator is included in the                    language.  Lempp hopes that strategies from the solution to the                 deep degree problem (with Slaman) will help with the necessary                  embeddings of homomorphisms of partial orders into these sets of                degrees.  Secondly, Lempp will investigate the existence of a                   join operation in the r.e. degrees modulo some equivalence                      relation defined by iterated jumps.  In a forcing argument, Lempp               has already shown that the join does not necessarily exist in the               Turing degrees modulo this equivalence relation.  Furthermore,                  Lempp plans to conclude work begun with Cooper and Watson by                    proving an extension of the nondensity theorem in the d.r.e.                    degrees.  Finally, Lempp intends to continue his work in index                  sets.  In his thesis, Lempp has exhibited a large family of such                index sets for r.e. sets the r.e. supersets of which form a                     Boolean algebra; he now plans to look at the non-Boolean algebra                case and at index sets of r.e. degrees.  Recursion theory being                 the study of the theoretical limits of computability, such                      investigations when completed may well renew contact with their                 original inspiration in the world of electronic computers.
{'FirstName': 'Steffen', 'LastName': 'Lempp', 'PI_MID_INIT': None, 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Steffen Lempp', 'EmailAddress': 'lempp@math.wisc.edu', 'NSF_ID': '000306772', 'StartDate': '06/15/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'Yale University', 'CityName': 'NEW HAVEN', 'ZipCode': '065113572', 'PhoneNumber': '2037854689', 'StreetAddress': '150 MUNSON ST', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'Connecticut', 'StateCode': 'CT', 'CONGRESSDISTRICT': '03', 'CONGRESS_DISTRICT_ORG': 'CT03', 'ORG_UEI_NUM': 'FL6GV84CKN57', 'ORG_LGL_BUS_NAME': 'YALE UNIV', 'ORG_PRNT_UEI_NUM': 'FL6GV84CKN57'}
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{'Code': '1267', 'Text': 'TOPOLOGY'}
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