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Communications in Algebra, 1974
It is a well-known result that the direct sum of any family of injective modules over a Noetherian ring is injective. Conversely, if A is a ring with the property that the direct sum of any family of injective modules is injective H. Bass [1] has shown that A is Noetherian.
B. Sarath, K. Varadarajan
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It is a well-known result that the direct sum of any family of injective modules over a Noetherian ring is injective. Conversely, if A is a ring with the property that the direct sum of any family of injective modules is injective H. Bass [1] has shown that A is Noetherian.
B. Sarath, K. Varadarajan
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On the extended direct sum conjecture
Proceedings of the twenty-first annual ACM symposium on Theory of computing - STOC '89, 1989We consider the quadratic complexity of certain sets of quadratic forms. We study a classes of direct sums of quadratic forms. For these classes of problems we show that the complexity of one direct sum is the sum of the complexity of the summands and that every minimal quadratic algorithm for computing the direct sums is a direct-sum algorithm.
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DIRECT SUMS OF OPERATOR SPACES
Journal of the London Mathematical Society, 2001It is proved that if X and Y are operator spaces such that every completely bounded operator from X into Y is completely compact and Z is a completely complemented subspace of X [oplus ] Y, then there exists a completely bounded automorphism τ: X [oplus ] Y → X [oplus ] Y with completely bounded inverse such that τZ = X0 [oplus ] Y0, where ...
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Direct Sums and Direct Products
2015The concept of direct sum is of utmost importance for the theory. This is mostly due to two facts: first, if we succeed in decomposing a group into a direct sum, then it can be studied by investigating the summands separately, which are, in numerous cases, simpler to deal with.
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2002
In Theorem 2.6 we obtained, for an inner product space V and a finite-dimensional subspace W of V, a direct sum decomposition of the form V = W ⊕W⊥. We now consider the following general notion.
T. S. Blyth, E. F. Robertson
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In Theorem 2.6 we obtained, for an inner product space V and a finite-dimensional subspace W of V, a direct sum decomposition of the form V = W ⊕W⊥. We now consider the following general notion.
T. S. Blyth, E. F. Robertson
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1974
For each ring R we have derived several module categories—among these the category R M of left R-modules. This derivation is not entirely reversible for, in general, R M does not characterize R. However, as we shall see in Chapter 6 it does come close. Thus, we can expect to uncover substantial information about R by mining R M.
Frank W. Anderson, Kent R. Fuller
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For each ring R we have derived several module categories—among these the category R M of left R-modules. This derivation is not entirely reversible for, in general, R M does not characterize R. However, as we shall see in Chapter 6 it does come close. Thus, we can expect to uncover substantial information about R by mining R M.
Frank W. Anderson, Kent R. Fuller
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2002
If A and B are non-empty subsets of a vector space V over a field F then the subspace spanned by A ∪ B, i.e. the smallest subspace of V that contains both A and B, is the set of linear combinations of elements of A ∪ B. In other words, it is the set of elements of the form $$ [\sum\limits_{i = 1}^m {{\lambda _i}} {a_i} + \sum\limits_{j = 1}^n {{\mu
T. S. Blyth, E. F. Robertson
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If A and B are non-empty subsets of a vector space V over a field F then the subspace spanned by A ∪ B, i.e. the smallest subspace of V that contains both A and B, is the set of linear combinations of elements of A ∪ B. In other words, it is the set of elements of the form $$ [\sum\limits_{i = 1}^m {{\lambda _i}} {a_i} + \sum\limits_{j = 1}^n {{\mu
T. S. Blyth, E. F. Robertson
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On the extent of the injectivity of direct sums of modules
Quaestiones Mathematicae, 2023Sérgio R López-Permouth, Bulent Sarac
exaly