Ruka hadi maudhui
The Lumenary
Shahada ya kwanza (juu)AlgebraImepangwa

Groups

Groups and subgroups, cyclic, dihedral and symmetric groups, cosets and Lagrange's theorem, homomorphisms and normal subgroups, and group actions with the orbit–stabiliser theorem.

math.algebra.groups

Somo la mada hii bado halijaandikwa. Muhtasari ulio hapa chini ni sehemu ya ramani ya mtaala na haujakaguliwa.

Inajengwa juu ya

Masharti ya awali ya lazima 13 (hadi chini kabisa)

Utajifunza

  • Work with cyclic, dihedral and symmetric groups, computing orders of elements and subgroups.
  • Prove Lagrange's theorem using cosets as equivalence classes.
  • Identify kernels and images of homomorphisms and recognise normal subgroups.
  • Apply the orbit–stabiliser theorem and Burnside's lemma to counting problems.

Fasili

  • A subgroup is a subset that contains the identity and is closed under the operation and under inverses.
  • The left coset of H containing g is gH = {gh : h ∈ H}.
  • A subgroup N is normal if gNg⁻¹ = N for every g in the group.
  • An action of G on a set X is a map G × X → X with e · x = x and g · (h · x) = (gh) · x.

Nadharia

  • Lagrange: the order of a subgroup of a finite group divides the order of the group.
  • Every subgroup of a cyclic group is cyclic; up to isomorphism the cyclic groups are ℤ and ℤ/nℤ.
  • The kernels of group homomorphisms are exactly the normal subgroups.
  • Orbit–stabiliser: for a finite group, |G · x| = |G| / |G_x|.
  • Cayley: every group is isomorphic to a group of permutations of some set.

Mawazo potofu ya kawaida

  • Believing the converse of Lagrange's theorem: A₄ has order 12 but no subgroup of order 6.
  • Thinking every subgroup is normal.
  • Assuming groups are commutative.

Inaelekea kwa

Ugunduzi wa hiari

Njia za kujifunza

Usomaji zaidi

  • Michael Artin, Algebra (1991)
  • David S. Dummit and Richard M. Foote, Abstract Algebra