Mathlib
Atlas
Algebra
Pathway VII
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Algebraic structures and transformations
Magmas, groups, homomorphisms — a set with an operation, and the maps that preserve it.
01
Groups
A group is a set with an associative operation, identities, and inverses. Cyclic groups are clocks.
4 min
02
Homomorphisms
A homomorphism is a map that preserves the operation. Kernels are the stuff sent to the identity.
4 min
03
Group actions
A group transforms a set. Orbits partition the set; stabilizers are the symmetries of a point.
4 min
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