Edward M. Reingold (born 1945) is a computer scientist active in the fields of algorithms, data structures, graph drawing, and calendrical calculations.
In 1996 he was inducted as a Fellow of the Association for Computing Machinery. [1]
In 2000 he retired from University of Illinois at Urbana-Champaign and was a professor of computer science and applied mathematics at the Illinois Institute of Technology until his retirement in 2019. [2]
He has co-authored the standard text on calendrical calculations, Calendrical Calculations , with Nachum Dershowitz. [3] [4] [5] [6]
In 1981 he was the co-author, with John Tilford, of the canonical paper "Tidier Drawings of Trees" which described a method, now known as the Reingold-Tilford algorithm, to produce more aesthetically pleasing drawing of binary (and by extension, m-ary) trees .
In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the naked eye, except when it is silhouetted against the Sun during a solar eclipse.
The Tabular Islamic calendar is a rule-based variation of the Islamic calendar. It has the same numbering of years and months, but the months are determined by arithmetical rules rather than by observation or astronomical calculations. It was developed by early Muslim astronomers of the second hijra century to provide a predictable time base for calculating the positions of the moon, sun, and planets. It is now used by historians to convert an Islamic date into a Western calendar when no other information is available. Its calendar era is the Hijri year. An example is the Fatimid or Misri calendar.
The New Calendarists are Eastern Orthodox churches that adopted the Revised Julian calendar.
Zohar Manna was an Israeli-American computer scientist who was a professor of computer science at Stanford University.
Before Present (BP) years, also known as "time before present" or "years before present (YBP)", is a time scale used mainly in archaeology, geology, and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because the "present" time changes, standard practice is to use 1 January 1950 as the commencement date (epoch) of the age scale. The abbreviation "BP" has been interpreted retrospectively as "Before Physics", which refers to the time before nuclear weapons testing artificially altered the proportion of the carbon isotopes in the atmosphere, which scientists must now account for.
Vṛścika(वृश्चिक), also referred to as Vrishchika or Vrschika, is a month in the Indian solar calendar. It corresponds to the zodiacal sign of Scorpio, and approximately overlaps with the later half of November and first half of December in the Gregorian calendar.
Omer Reingold is an Israeli computer scientist. He is the Rajeev Motwani professor of Computer Science in the Computer Science Department at Stanford University and the director of the Simons Collaboration on the Theory of Algorithmic Fairness. He received a PhD in computer science at Weizmann in 1998 under Moni Naor. He received the 2005 Grace Murray Hopper Award for his work in finding a deterministic logarithmic-space algorithm for st-connectivity in undirected graphs. He, along with Avi Wigderson and Salil Vadhan, won the Gödel Prize (2009) for their work on the zig-zag product. He became a Fellow of the Association for Computing Machinery in 2014 "For contributions to the study of pseudorandomness, derandomization, and cryptography."
A calendrical calculation is a calculation concerning calendar dates. Calendrical calculations can be considered an area of applied mathematics. Some examples of calendrical calculations:
Rata Die (R.D.) is a system for assigning numbers to calendar days, independent of any calendar, for the purposes of calendrical calculations. It was named by Howard Jacobson.
Karkaṭa, also referred to as Karka or Karkatha, is a month in the Indian solar calendar. It corresponds to the zodiacal sign of Cancer, and overlaps approximately with the later half of July and early half of August in the Gregorian calendar.
Yuri Gurevich, Professor Emeritus at the University of Michigan, is an American computer scientist and mathematician and the inventor of abstract state machines.
In computing, an epoch is a fixed date and time used as a reference from which a computer measures system time. Most computer systems determine time as a number representing the seconds removed from a particular arbitrary date and time. For instance, Unix and POSIX measure time as the number of seconds that have passed since Thursday 1 January 1970 00:00:00 UT, a point in time known as the Unix epoch. Windows NT systems, up to and including Windows 11 and Windows Server 2022, measure time as the number of 100-nanosecond intervals that have passed since 1 January 1601 00:00:00 UTC, making that point in time the epoch for those systems. Computing epochs are almost always specified as midnight Universal Time on some particular date.
Roberto Tamassia is an American Italian computer scientist, the Plastech Professor of Computer Science at Brown University, and served as the chair of the Brown Computer Science department from 2007 to 2014. His research specialty is in the design and analysis of algorithms for graph drawing, computational geometry, and computer security; he is also the author of several textbooks.
Nachum Dershowitz is an Israeli computer scientist, known e.g. for the Dershowitz–Manna ordering and the multiset path ordering used to prove termination of term rewrite systems.
Meṣa, or Mesha (मेष), is a month in the Indian solar calendar. It corresponds to the zodiacal sign of Aries, and overlaps with about the second half of April and about the first half of May in the Gregorian calendar. Generally Mesha month starts on 13th or 14th of April, called as Mesha Sankranti.
Vṛṣabha, or Vrishabha, is a month in the Indian solar calendar. It corresponds to the zodiacal sign of Taurus, and overlaps with about the second half of May and about the first half of June in the Gregorian calendar. The first day of the month is called Vrishbha Sankranti, and it generally falls on May 14 or 15.
Takao Nishizeki was a Japanese mathematician and computer scientist who specialized in graph algorithms and graph drawing.
Mithuna is a month in the Indian solar calendar. It corresponds to the zodiacal sign of Gemini, and overlaps with about the second half of June and about the first half of July in the Gregorian calendar.
Makara is a month in the Indian solar calendar. It corresponds to the zodiacal sign of Capricorn, and overlaps with about the later half of January and approximately early half of February in the Gregorian calendar.
Calendrical Calculations is a book on calendar systems and algorithms for computers to convert between them. It was written by computer scientists Nachum Dershowitz and Edward Reingold and published in 1997 by the Cambridge University Press. A second "millennium" edition with a CD-ROM of software was published in 2001, a third edition in 2008, and a fourth "ultimate" edition in 2018.