{{Short description|American computer scientist (1935–2011)}} {{Use dmy dates|date=September 2023}} {{Infobox person | name = Patrick C. Fischer | image = | caption = | birth_name = Patrick Carl Fischer | birth_date = December 3, 1935 | birth_place = St. Louis, Missouri, U.S. | death_date = {{death date and age|2011|8|26|1935|12|3}} | death_place = Rockville, Maryland, U.S. | death_cause = | resting_place = | resting_place_coordinates = | other_names = | known_for = | education = University of Michigan (BA, MBA)<br>Massachusetts Institute of Technology (PhD) | employer = Vanderbilt University | occupation = Computer scientist | title = | term = | predecessor = | successor = | party = | boards = | spouse = | children = | parents = Carl H. Fischer | relatives = }} '''Patrick Carl Fischer''' (December 3, 1935 – August 26, 2011) was an American computer scientist, a noted researcher in computational complexity theory and database theory, and a target of the Unabomber.<ref name="fortnow">{{citation|first=Lance|last=Fortnow|authorlink=Lance Fortnow|title=Patrick Fischer (1935-2011)|url=http://blog.computationalcomplexity.org/2011/08/patrick-fischer-1935-2011.html|date=August 29, 2011|access-date=3 September 2011|archive-date=10 October 2011|archive-url=https://web.archive.org/web/20111010060406/http://blog.computationalcomplexity.org/2011/08/patrick-fischer-1935-2011.html|url-status=live}}.</ref><ref name="nyt">{{citation|archiveurl=https://archive.today/20120906043924/http://www.nytimes.com/2011/08/31/us/31fischer.html?_r=1|archivedate=September 6, 2012|journal=New York Times|date=August 31, 2011|title=Patrick C. Fischer, Early Unabomber Target, Is Dead at 75|first=Paul|last=Vitello|url=https://www.nytimes.com/2011/08/31/us/31fischer.html?_r=1}} [http://www.post-gazette.com/news/obituaries/2011/09/03/Obituary-Patrick-C-Fischer-Computer-scientist-targeted-by-Unabomber/stories/201109030159 Alt URL] {{Webarchive|url=https://web.archive.org/web/20240509230019/https://www.post-gazette.com/news/obituaries/2011/09/03/Obituary-Patrick-C-Fischer-Computer-scientist-targeted-by-Unabomber/stories/201109030159 |date=9 May 2024 }}.</ref><ref name="lat">{{citation|journal=Los Angeles Times|date=September 3, 2011|title=Patrick Fischer dies at 75; target of Unabomber|url=https://www.latimes.com/local/obituaries/la-me-patrick-fischer-20110903-story.html|access-date=11 October 2015|archive-date=1 November 2017|archive-url=https://web.archive.org/web/20171101045457/http://articles.latimes.com/2011/sep/03/local/la-me-patrick-fischer-20110903|url-status=live}}</ref><ref name="psu">{{citation|title=Patrick Fischer, Former Professor and Department Head of Computer Science at Penn State, Dies|url=http://www.cse.psu.edu/20110830-1|publisher=Pennsylvania State University Department of Computer Science and Engineering|accessdate=2011-09-03|archive-date=6 September 2011|archive-url=https://web.archive.org/web/20110906014654/http://www.cse.psu.edu/20110830-1|url-status=live}}.</ref><ref name="vandy">{{citation|last1=Patterson |first1=Jim |title=Patrick Fischer, former computer science chair, dies|journal=Vanderbilt News|date=August 26, 2011|url=http://news.vanderbilt.edu/2011/08/patrick-fischer-former-engineering-chair-dies/|access-date=3 September 2011|archive-date=9 May 2024|archive-url=https://web.archive.org/web/20240509225747/https://news.vanderbilt.edu/2011/08/26/patrick-fischer-former-engineering-chair-dies/|url-status=live}}.</ref>
==Biography== Fischer was born December 3, 1935, in St. Louis, Missouri.<ref name="nyt"/><ref name="lat"/> His father, Carl H. Fischer, became a professor of actuarial mathematics at the University of Michigan in 1941,<ref>{{citation|url=http://um2017.org/faculty-history/faculty/carl-h-fischer|archive-url=https://archive.today/20120716075946/http://um2017.org/faculty-history/faculty/carl-h-fischer|url-status=dead|archive-date=16 July 2012|contribution=Carl H. Fischer|title=University of Michigan Faculty History Project|accessdate=3 September 2011}}.</ref> and the family moved to Ann Arbor, Michigan, where he grew up.<ref name="nyt"/> Fischer himself went to the University of Michigan, receiving a bachelor's degree in 1957<ref name="nyt"/><ref name="lat"/> and an MBA in 1958.<ref>{{citation|journal=Dividend, the Magazine of the Graduate School of Business Administration|publisher=University of Michigan|date=Fall 1981|url=http://deepblue.lib.umich.edu/bitstream/2027.42/50729/2/1981-fall-dividend-text.pdf|title=Patrick C. Fischer|page=43|access-date=28 September 2011|archive-date=30 March 2012|archive-url=https://web.archive.org/web/20120330131914/http://deepblue.lib.umich.edu/bitstream/2027.42/50729/2/1981-fall-dividend-text.pdf|url-status=live}}.</ref> He went on to graduate studies at the Massachusetts Institute of Technology, earning a Ph.D. in 1962 under the supervision of Hartley Rogers, Jr., with a thesis on the subject of recursion theory.<ref name="nyt"/><ref name="lat"/><ref name="mg">{{mathgenealogy|name=Patrick Carl Fischer|id=13297}}</ref>
After receiving his Ph.D. in 1962, Fischer joined the faculty of Harvard University as an assistant professor of applied mathematics; his students at Harvard included Albert R. Meyer, through whom Fischer has over 250 academic descendants. as well as noted computer scientists Dennis Ritchie and Arnold L. Rosenberg.<ref name="mg"/> In 1965, he moved to a tenured position as associate professor of computer science at Cornell University. After teaching at the University of British Columbia from 1967 to 1968 (where he met his second wife Charlotte Froese) he moved to the University of Waterloo where he became a professor of applied analysis and computer science. At Waterloo, he was department chair from 1972 to 1974. He then moved to Pennsylvania State University in 1974, where he headed the computer science department, and moved again to Vanderbilt University as department chair in 1980.<ref name="fortnow"/><ref name="nyt"/><ref name="lat"/> He taught at Vanderbilt for 18 years, and was chair for 15 years.<ref name="vandy"/> He retired in 1998,<ref name="nyt"/> and died of stomach cancer on August 26, 2011, in Rockville, Maryland.<ref name="fortnow"/><ref name="nyt"/><ref name="lat"/>
Like his father, Fischer became a fellow of the Society of Actuaries.<ref>{{citation|url=http://www.actuary.org/archives/pdf/yearbook/yearbook_1969.pdf|title=1969 Year Book|author=American Academy of Actuaries|year=1969|publisher=University of Chicago|page=33}}.</ref> Fischer's second wife, Charlotte Froese Fischer, was also a computer science professor at Vanderbilt University and the University of British Columbia, and his brother, Michael J. Fischer, is a computer science professor at Yale University.<ref name="lat"/><ref name="fortnow"/>
==Research== Fischer's thesis research concerned the effects of different models of computation on the efficiency of solving problems. For instance, he showed how to generate the sequence of prime numbers using a one-dimensional cellular automaton, based on earlier solutions to the firing squad synchronization problem,<ref>{{citation | last = Fischer | first = Patrick C. | doi = 10.1145/321281.321290 | issue = 3 | journal = Journal of the ACM | pages = 388–394 | title = Generation of primes by a one-dimensional real-time iterative array | volume = 12 | year = 1965| s2cid = 18619107 | doi-access = free }}.</ref> and his work in this area set the foundation for much later work on parallel algorithms.<ref name="fortnow"/> With Meyer and Rosenberg, Fischer performed influential early research on counter machines, showing that they obeyed time hierarchy and space hierarchy theorems analogous to those for Turing machines.<ref>{{citation | last1 = Fischer | first1 = Patrick C. | last2 = Meyer | first2 = A. R. | author2-link = Albert R. Meyer | last3 = Rosenberg | first3 = Arnold L. | author3-link = Arnold L. Rosenberg | journal = Mathematical Systems Theory | mr = 0235932 | pages = 265–283 | title = Counter machines and counter languages | volume = 2 | issue = 3 | year = 1968 | doi=10.1007/bf01694011| s2cid = 13006433 }}.</ref>
Fischer was an early leader in the field of computational complexity, and helped establish theoretical computer science as a discipline separate from mathematics and electrical engineering.<ref name="psu"/> He was the first chair of SIGACT, the Special Interest Group on Algorithms and Computation Theory of the Association for Computing Machinery, which he founded in 1968.<ref name="fortnow"/><ref name="nyt"/> He also founded the annual Symposium on Theory of Computing, which together with the Symposium on Foundations of Computer Science is one of the two flagship conferences in theoretical computer science, and he served five times as chair of the conference.<ref name="fortnow"/>
In the 1980s, Fischer's research interests shifted to database theory. His research in that area included the study of the semantics of databases, metadata, and incomplete information.<ref name="fortnow"/> Fischer did important work defining the nested relational model of databases, in which the values in the cells of a relational database may themselves be relations,<ref>{{citation | last1 = Thomas | first1 = Stan J. | last2 = Fischer | first2 = Patrick C. | journal = Advances in Computing Research | pages = 269–307 | title = Nested Relational Structures | volume = 3 | year = 1986}}.</ref><ref>{{citation | last1 = Fischer | first1 = Patrick C. | last2 = Thomas | first2 = Stan J. | contribution = Operators for Non-First-Normal-Form Relations | pages = 464–475 | title = Proceedings of the 7th International Computer Software Applications Conference (IEEE COMPSAC '83) | year = 1983}}.</ref> and his work on the mathematical foundations of database query languages became central to the databases now used by major web servers worldwide.<ref name="nyt"/>
Fischer was also an expert in information systems and their use by educational institutions.<ref name="lat"/><ref name="vandy"/>
==Unabomber target== Ted Kaczynski, known as the Unabomber, was a graduate student of mathematics at the University of Michigan, where Fischer's father was a professor.<ref name="lat"/> In 1982, Kaczynski sent the fifth of his mail bombs to Fischer, at his Penn State address; it was forwarded to Vanderbilt, where it was opened on May 5 by Fischer's secretary, Janet Smith, who was hospitalized for three weeks after the attack.<ref name="lat"/><ref name="nyt"/> Fischer claimed not to have ever met Kaczynski,<ref name="fortnow"/><ref name="nyt"/> and speculated that he was targeted because he "went from pure math to theoretical computer science."<ref name="nyt"/>
==References== {{reflist|30em}}
{{Ted Kaczynski}} {{Authority control}}
{{DEFAULTSORT:Fischer, Patrick C.}} Category:1935 births Category:2011 deaths Category:American theoretical computer scientists Category:Cellular automatists Category:Database researchers Category:University of Michigan College of Literature, Science, and the Arts alumni Category:MIT School of Science alumni Category:Harvard University faculty Category:Cornell University faculty Category:Academic staff of the University of Waterloo Category:Pennsylvania State University faculty Category:Vanderbilt University faculty Category:Unabomber targets Category:Ross School of Business alumni Category:Scientists from Ann Arbor, Michigan