In mathematics, a group scheme is a type of algebro-geometric object equipped with a composition law.
 Group schemes arise naturally as symmetries of schemes, and they generalize algebraic groups, in the sense that all algebraic groups have group scheme structure, but group schemes are not necessarily connected, smooth, or defined over a field.
 This extra generality allows one to study richer infinitesimal structures, and this can help one to understand and answer questions of arithmetic significance.
 The category of group schemes is somewhat better behaved than that of group varieties, since all homomorphisms have kernels, and there is a well-behaved deformation theory.
 Group schemes that are not algebraic groups play a significant role in arithmetic geometry and algebraic topology, since they come up in contexts of Galois representations and moduli problems.
 The initial development of the theory of group schemes was due to Alexander Grothendieck, Michel Raynaud and Michel Demazure in the early 1960s.
Rafferty or (Russian: Рафферти , "Rafferty " ) is a Soviet 1980 drama television film directed by Semyon Aranovich and based on the novel by American writer Lionel White.
In mathematics, the Demazure conjecture is a conjecture about representations of algebraic groups over the integers made by .
 The conjecture implies that many of the results of his paper can be extended from complex algebraic groups to algebraic groups over fields of other characteristics or over the integers.
 showed that Demazure's conjecture (for classical groups) follows from their work on standard monomial theory, and Peter Littelmann extended this to all reductive algebraic groups.
Gary Michael Seitz (born 1943) is an American mathematician, a Fellow of the American Mathematical Society and a College of Arts and Sciences Distinguished Professor Emeritus in Mathematics at the University of Oregon.
 He received his Ph.D. from the University of Oregon in 1968, where his adviser was Charles W. Curtis.
 Seitz specializes in the study of algebraic and finite groups.
 Seitz has been active in the effort to exploit the relationship between algebraic groups and the finite groups of Lie type, in order to study the structure and representations of groups in the latter class.
 Such information is important in its own right, but was also critical in the classification of the finite simple groups, a major achievement of 20th century mathematics.
 Seitz made contributions to the classification of finite simple groups, such as those containing standard subgroups of Lie type.
 Following the classification, he pioneered the study of the subgroup structure of simple algebraic groups, and as an application went a long way towards solving the maximal subgroup problem for finite groups.
 For this work he received the Creativity Award from the National Science Foundation in 1991.
In mathematics, the Gershgorin circle theorem may be used to bound the spectrum of a square matrix.
 It was first published by the Soviet mathematician Semyon Aronovich Gershgorin in 1931.
 The spelling of S. A. Gershgorin's name has been transliterated in several different ways, including Geršgorin, Gerschgorin, Gershgorin, Hershhorn, and Hirschhorn.
In mathematics, Theory of Lie groups is a series of books on Lie groups by .
 The first in the series was one of the earliest books on Lie groups to treat them from the global point of view, and for many years was the standard text on Lie groups.
 The second and third volumes, on algebraic groups and Lie algebras, were written in French, and later reprinted bound together as one volume.
 Apparently further volumes were planned but not published, though his lectures on the classification of semisimple algebraic groups could be considered as a continuation of the series.
Semyon Aronovich Gershgorin (August 24, 1901 – May 30, 1933) was a Soviet (born in Pruzhany, Belarus, Russian Empire) mathematician.
 He began as a student at the Petrograd Technological Institute in 1923, became a Professor in 1930, and was given an appointment at the Leningrad Mechanical Engineering Institute in the same year.
 His contributions include the Gershgorin circle theorem.
The Year of the Dog (Russian: Год собаки , "God sobaki " ) is a 1994 Russian drama film directed by Semyon Aranovich.
 It was entered into the 44th Berlin International Film Festival where it won the Silver Bear for an outstanding artistic contribution.
Confrontation or (Russian: Противостояние , "Protivostoyanie " ) is a 1985 Soviet six-part television film directed by Semyon Aranovich based on the novel by Yulian Semyonov.
Anatoly Ivanovich Maltsev (also: Malcev, Mal'cev; Russian: Анато́лий Ива́нович Ма́льцев; 27 November N.S./14 November O.S. 1909, Moscow Governorate – 7 June 1967, Novosibirsk) was born in Misheronsky, near Moscow, and died in Novosibirsk, USSR.
 He was a mathematician noted for his work on the decidability of various algebraic groups. Malcev algebras (generalisations of Lie algebras) are named after him.

Question: Which mathematician contributed most to the decidability of various algebraic groups, Anatoly Maltsev or Semyon Aranovich Gershgorin?
Answer: Anatoly Ivanovich Maltsev