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group in nLab


classifying space in nLab

For example, Eilenberg-MacLane spaces K ( G , n ) K(G,n) have the property that homotopy classes of maps into them are in bijection with cohomology groups H n ( ...

E₇ in nLab

One of the exceptional Lie groups. 2. Definition. Consider the vector space. W ≔ ∧ 2 ...

E₉ in nLab

Contents. 1. Idea; 2. Properties. Representations of maximal compact subalgebra; As U-duality group of 2d supergravity.

Introduction to Stable Homotopy Theory in nLab

A double loop space is a group with some commutativity structure (“Eckmann-Hilton argument”), a triple loop space has more commutativity ...

G-set in nLab

Given a topological group G G , a (continuous) G G -set is a set X X equipped with a continuous group action μ : G × X → X \mu: G \times X \to X ...

groupal model for universal principal infinity-bundles in nLab

For G G a model for an ∞-group, there is often a model for the universal principal ∞-bundle E G \mathbf{E}G that itself carries a group ...

line object in nLab

This entry discusses line objects, their multiplicative groups and additive groups in generality. For the traditional notions see at affine line.

H-space in nLab

Mapping spaces into H-groups ... If K K is an H H -group then for any topological space X X , the set of homotopy classes [ X , K ] [X,K] has a ...

ring in nLab

Notably when abelian groups are generalized to their analogs in stable homotopy theory, namely to spectra, the corresponding internal monoids ...

club in nLab

Examples of this phenomenon include the monad for monoidal categories, symmetric monoidal categories, braided monoidal categories, categories ...

opposite category in nLab

Opposite of the opposite. The opposite of an opposite category is the original category: ( C op ) op = C . (C^{op})^{op} = C \,. This is also ...

carrying in nLab

Being an abelian group, every delooping n-groupoid B n ( ℤ / 10 ) \mathbf{B}^n (\mathbb{Z}/{10}) exists. Carrying is a 2-cocycle in the group ...

heap in nLab

Structure groups of heaps · (i) the bijections t ( a , b , − ) t(a,b,-) and t ( a ′ , b ′ , − ) t(a',b',-) coincide · (ii) t ( a , b , b ′ ) = a ′ ...

G₂ in nLab

As such, the group G 2 G_2 is a higher analog of the symplectic group (which is the group that preserves a canonical 2-form on any ℝ 2 n ...

order in nLab

A mostly unrelated notion from group theory is order of a group, meaning the cardinality | G | |G| of the underlying set of a group G G , ...

conjugacy class in nLab

For any finite group the number of its conjugacy classes is equal to the number of its irreducible representations. For finite groups of Lie ...

group character in nLab

The collection of characters is itself an abelian group under the pointwise multiplication, this is called the character lattice Hom ( G , k × ) ...

E₈ in nLab

By the above discussion of homotopy groups, it follows (by Chern-Weil theory) that the first invariant polynomials on the Lie algebra 𝔢 8 \ ...

concrete structure in nLab

This is the original notion of concrete group due to Évariste Galois. Abstracting from this, we get the modern notion of abstract group as a set ...

homomorphism in nLab

It is a theorem that a semigroup homomorphism between groups must be a monoid homomorphism (and additionally must preserve inverse elements, ...