The abacus, also called a counting frame, is a calculating tool which has been used since ancient times. It was used in the ancient Near East, Europe, China, and Russia, millennia before the adoption of the Hindu-Arabic numeral system. The exact origin of the abacus has not yet emerged. It consists of rows of movable beads, or similar objects, strung on a wire. They represent digits. One of the two numbers is set up, and the beads are manipulated to perform an operation such as addition, or even a square or cubic root.
Christian Felix Klein was a German mathematician and mathematics educator, known for his work with group theory, complex analysis, non-Euclidean geometry, and on the associations between geometry and group theory. His 1872 Erlangen program, classifying geometries by their basic symmetry groups, was an influential synthesis of much of the mathematics of the time.
Julius Plücker was a German mathematician and physicist. He made fundamental contributions to the field of analytical geometry and was a pioneer in the investigations of cathode rays that led eventually to the discovery of the electron. He also vastly extended the study of Lamé curves.
Rudolf Otto Sigismund Lipschitz was a German mathematician who made contributions to mathematical analysis and differential geometry, as well as number theory, algebras with involution and classical mechanics.
A mental calculator or human calculator is a person with a prodigious ability in some area of mental calculation.
Constantin Carathéodory was a Greek mathematician who spent most of his professional career in Germany. He made significant contributions to real and complex analysis, the calculus of variations, and measure theory. He also created an axiomatic formulation of thermodynamics. Carathéodory is considered one of the greatest mathematicians of his era and the most renowned Greek mathematician since antiquity.
Eduard Study, more properly Christian Hugo Eduard Study, was a German mathematician known for work on invariant theory of ternary forms (1889) and for the study of spherical trigonometry. He is also known for contributions to space geometry, hypercomplex numbers, and criticism of early physical chemistry.
Carl Gottfried Neumann was a German mathematician.
The Decamentathlon is a multi disciplined games event that was created as part of the first Mind Sports Olympiad. It was founded to try to find the best games all-rounder in the world and hence possibly the best games player. It was given a prize fund of £10,000 for the inaugural competition, that equalled that of the highest funded event at the first MSO sponsored by Skandia. However, the other events were spread over multiple playing sessions whereas the Decamentathlon was held over just a single session. This event was initially hailed as the MSO flagship event. Although, the Mind Sports Olympiad's other new event the Pentamind has since become regarded as the more significant event despite not having a fixed format.
Mikhail Semyonovich Tsvet was a Russian-Italian botanist who invented chromatography. His last name is Russian for "colour" and is also the root word of "flower."
Heinrich Franz Friedrich Tietze was an Austrian mathematician, famous for the Tietze extension theorem on functions from topological spaces to the real numbers. He also developed the Tietze transformations for group presentations, and was the first to pose the group isomorphism problem. Tietze's graph is also named after him; it describes the boundaries of a subdivision of the Möbius strip into six mutually-adjacent regions, found by Tietze as part of an extension of the four color theorem to non-orientable surfaces.
Kurt Wilhelm Sebastian Hensel was a German mathematician born in Königsberg.
George Lane is a British mental calculator and author. He is a five-time gold medalist in the Mental Calculations event at the annual Mind Sports Olympiad, and is one of only five Grandmasters of Mental Calculation, as recognised by the Mind Sports Organisation. George is a regular facilitator at the annual Junior Mental Calculation World Championship. He has written two books.
Stefan Bergman was a Congress Poland-born American mathematician whose primary work was in complex analysis. His name is also written Bergmann; he dropped the second "n" when he came to the U. S. He is best known for the kernel function he discovered while at University of Berlin in 1922. This function is known today as the Bergman kernel. Bergman taught for many years at Stanford University, and served as an advisor to several students.
Willem Klein, also known as Wim Klein or under his stage names Pascal and Willy Wortel, was a Dutch mathematician of Jewish ancestry, famous for being able to carry out very complicated calculations in his head very fast. On 27 August 1976, he calculated the 73rd root of a 500-digit number in 2 minutes and 43 seconds. This feat was recorded by the Guinness Book of Records.
Alexis Lemaire is a mental calculation world record holder. He holds a Ph.D. in Computer Science related to artificial intelligence from the University of Reims. He is also the owner of world records for mentally calculating the 13th root of 100-digit numbers and 200-digit numbers.
Dr Amit Garg is an Indian mathematician and mental calculator. He currently works as founder and Chief Scientist at ORMAE, a firm registered in USA, UAE & India which engages in building innovative products, consulting and training in Operations Research and Data Science.
Goswin Karl Uphues was a German philosopher. He taught at a gymnasium in Aarau before becoming a professor at the University of Halle.
Rudolf Paul Joachim Kochendörffer was a German mathematician who was a Professor of mathematics in the University of Rostock specialising in algebra, Group theory and theory of finite groups and their representation. During World War II, Kochendörffer worked as a mathematical cryptanalyst in the mathematical referat of Inspectorate 7/IV, that would later become part of Referat I of Group IV of the General der Nachrichtenaufklärung, the signals intelligence agency of the Wehrmacht and was known as a cryptographic tester of the Enigma cipher machine. Kochendörffer was a Member of the Scientific Advisory Council for Mathematics at the State Secretariat for the Higher and Specialist Schools of the GDR, a staff member of Mathematical Reviews and collaborated with the Zentralblatt MATH
Friedrich Bachmann was a German mathematician who specialised in geometry and group theory.
