Examples of using Direct sum in English and their translations into Russian
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A symmetric Lie algebra decomposes into the direct sum of its socle and cosocle.
A union of mutually disjoint unary algebras is called their direct sum.
The boundary map is defined as the direct sum of boundary maps on each of the terms of the sheet.
One says that a group has the complete reducibility property if every representation decomposes as a direct sum of irreducible representations.
Some coproducts, such as Direct sum and Wedge sum, are named to evoke their connection with addition.
Non-commutative local rings arise naturally as endomorphism rings in the study of direct sum decompositions of modules over some other rings.
If a given Lie algebra g is a direct sum of its ideals I1,…, In, then the Killing form of g is the direct sum of the Killing forms of the individual summands.
In this case, each sheet is a doubly graded module, so it decomposes as a direct sum of terms with one term for each possible bidegree.
Every projective module is flat. simple module A simple module is a nonzero module whose only submodules are zero and itself.indecomposable module An indecomposable module is a non-zero module that cannot be written as a direct sum of two non-zero submodules.
Every free abelian group may be described as a direct sum of copies of Z{\displaystyle\mathbb{Z}}, with one copy for each member of its basis.
Every finite-dimensional unitary representation on a Hermitian vector space V{\displaystyle V}is the direct sum of irreducible representations.
By Frobenius reciprocity, on K they decompose as a direct sum of the irreducible representations of K with dimensions|k|+ 2m+ 1 with m a non-negative integer.
In particular every holomorphic vector bundle over C P 1{\displaystyle\mathbb{CP}^{1}} is a direct sum of holomorphic line bundles.
In particular, all such representations decompose as a direct sum of irreps, and the number of irreps of G{\displaystyle G} is equal to the number of conjugacy classes of G{\displaystyle G.
Let S{\displaystyle S} be a graded ring, where S⨁ i≥ 0 S i{\displaystyle S=\bigoplus_{i\geq 0}S_{i}}is the direct sum decomposition associated with the gradation.
Then:(M1) T{\displaystyle T}can be decomposed into a direct sum of cyclic torsion modules, each of the form R/ I{\displaystyle R/I} for some nonzero ideal I{\displaystyle I} of R{\displaystyle R.
Another consequence is that every compact Lie group has the complete reducibility property,meaning that all its finite-dimensional representations decompose as a direct sum of irreducible representations.
As a representation of K,each is isomorphic to the Hilbert space direct sum of all the odd dimensional irreducible representations of K SU2.
In category theory, the coproduct, or categorical sum, is a category-theoretic construction which includes as examples the disjoint union of sets and of topological spaces,the free product of groups, and the direct sum of modules and vector spaces.
This addition of morphism turns Ab into a preadditive category, and because the direct sum of finitely many abelian groups yields a biproduct, we indeed have an additive category.
Let G be a split reductive group over a field k, and let T be a split maximal torus in G; so T is isomorphic to(Gm)n for some n, with n called the rank of G. Every representation of T(as an algebraic group)is a direct sum of 1-dimensional representations.
By the Chinese Remainder Theorem,each R/ I{\displaystyle R/I} can further be decomposed into a direct sum of submodules of the form R/ P i{\displaystyleR/P^{i}}, where P i{\displaystyle P^{i}} is a power of a prime ideal.
This shows that the set End(G) of all endomorphisms of an abelian group forms a ring, the endomorphism ring of G. For example,the endomorphism ring of the abelian group consisting of the direct sum of m copies of Z/nZ is isomorphic to the ring of m-by-m matrices with entries in Z/nZ.
The action of the Lie algebra g{\displaystyle{\mathfrak{g}}} of G can be computed on the algebraic direct sum of the irreducible subspaces of K canbe computed explicitly and the it can be verified directly that the lowest-dimensional subspace generates this direct sum as a g{\displaystyle{\mathfrak{g}}}-module.
For the special case of a Lie algebra g{\displaystyle{\mathfrak{g}}} with a Cartan subalgebra h{\displaystyle{\mathfrak{h}}}, given an ordering of h{\displaystyle{\mathfrak{h}}},the Borel subalgebra is the direct sum of h{\displaystyle{\mathfrak{h}}} and the weight spaces of g{\displaystyle{\mathfrak{g}}} with positive weight.
One can see that from the representation theory point of view polynomials of the first degree can be identified with direct sum of the representations C n⊕⋯⊕ C n{\displaystyle\mathbb{C}^{n}\oplus\cdots\oplus\mathbb{C}^{n}}, here l-th subspace(l=1… m) is spanned by x i l{\displaystyle x_{il}}, i 1,…, n.
Each irreducible subrepresentation of SO(3) is finite-dimensional, and the SO(3)representation is reducible into a direct sum of irreducible finite-dimensional unitary representations of SO(3) if ΠH is unitary.
Over an arbitrary Dedekind domain one has(M3DD) P{\displaystyle P}is isomorphic to a direct sum of rank one projective modules: P≅ I 1⊕⋯⊕ I r{\displaystyle P\cong I_{1}\oplus\cdots\oplus I_{r.
The fundamental theorem of finite abelian groups states that every finite abelian group G can be expressed as the direct sum of cyclic subgroups of prime-power order; it is also known as the basis theorem for finite abelian groups.
Let T be the subgroup of diagonal matrices in G. Then the root-space decomposition expresses g l( n){\displaystyle{{\mathfrak{g}}l}(n)}as the direct sum of the diagonal matrices and the 1-dimensional subspaces indexed by the off-diagonal positions i, j.