Properties of groups

Imperfect group

In mathematics, in the area of algebra known as group theory, an imperfect group is a group with no nontrivial perfect quotients. Some of their basic properties were established in. The study of imperfect groups apparently began in. The class of imperfect groups is closed under extension and quotient groups, but not under subgroups. If G is a group, N, M are normal subgroups with G/N and G/M imperfect, then G/(N∩M) is imperfect, showing that the class of imperfect groups is a formation. The (restricted or unrestricted) direct product of imperfect groups is imperfect. Every solvable group is imperfect. Finite symmetric groups are also imperfect. The general linear groups PGL(2,q) are imperfect for q an odd prime power. For any group H, the wreath product H wr Sym2 of H with the symmetric group on two points is imperfect. In particular, every group can be embedded as a two-step subnormal subgroup of an imperfect group of roughly the same cardinality (2|H|2). (Wikipedia).

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Simple Groups - Abstract Algebra

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From playlist Abstract Algebra

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Product groups

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From playlist Abstract algebra

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From playlist Abstract algebra

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From playlist Modern Algebra - Chapter 15 (groups)

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From playlist Abstract Algebra

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From playlist Abstract Algebra - Entire Course

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From playlist Abstract algebra

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Abstract Algebra | The dihedral group

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From playlist Abstract Algebra

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From playlist Group theory

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NIP Henselian fields - F. Jahnke - Workshop 2 - CEB T1 2018

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From playlist 2018 - T1 - Model Theory, Combinatorics and Valued fields

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Pushing back the barrier of imperfection - F-V. Kuhlmann - Workshop 2 - CEB T1 2018

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From playlist 2018 - T1 - Model Theory, Combinatorics and Valued fields

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Tamagawa Numbers of Linear Algebraic Groups over (...) - Rosengarten - Workshop 2 - CEB T2 2019

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Pseudo-reductive groups by Brian Conrad

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Takeshi Saito - Upper ramification groups of local fields with imperfect residue fields (1/3)

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From playlist Franco-Asian Summer School on Arithmetic Geometry (CIRM)

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The Geometry of Data Assimilation 2 : Lenny Smith

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5. Imperfect Information and Dice

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Efficient algorythms to train supermodels - Schevenhoven - Workshop 2 - CEB T3 2019

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From playlist 2019 - T3 - The Mathematics of Climate and the Environment

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Normal subgroups

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From playlist Abstract algebra

Related pages

Perfect group | Wreath product | Group extension | Subgroup | Quotient group | Symmetric group | Mathematics | Solvable group | Algebra | Subnormal subgroup | Group theory | General linear group | Carter subgroup | Direct product of groups | Group (mathematics)