Nonnegative tensor ring(NTR) decomposition is a powerful tool for capturing the significant features of tensor objects while preserving the multi-linear structure of tensor data. The existing algorithms rely on freque...Nonnegative tensor ring(NTR) decomposition is a powerful tool for capturing the significant features of tensor objects while preserving the multi-linear structure of tensor data. The existing algorithms rely on frequent reshaping and permutation operations in the optimization process and use a shrinking step size or projection techniques to ensure core tensor nonnegativity, which leads to a slow convergence rate, especially for large-scale problems. In this paper, we first propose an NTR algorithm based on the modulus method(NTR-MM), which constrains core tensor nonnegativity by modulus transformation. Second, a low-rank approximation(LRA) is introduced to NTR-MM(named LRA-NTR-MM), which not only reduces the computational complexity of NTR-MM significantly but also suppresses the noise. The simulation results demonstrate that the proposed LRA-NTR-MM algorithm achieves higher computational efficiency than the state-of-the-art algorithms while preserving the effectiveness of feature extraction.展开更多
This paper investigates the connections between ring theory, module theory, and graph theory through the graph G(R)of a ring R. We establish that vertices of G(R)correspond to modules, with edges defined by the vanish...This paper investigates the connections between ring theory, module theory, and graph theory through the graph G(R)of a ring R. We establish that vertices of G(R)correspond to modules, with edges defined by the vanishing of their tensor product. Key results include the graph’s connectivity, a diameter of at most 3, and a girth of at most 7 when cycles are present. We show that the set of modules S(R)is empty if and only if R is a field, and that for semisimple rings, the diameter is at most 2. The paper also discusses module isomorphisms over subrings and localization, as well as the inclusion of G(T)within G(R)for a quotient ring T, highlighting that the reverse inclusion is not guaranteed. Finally, we provide an example illustrating that a non-finitely generated module M does not imply M⊗M=0. These findings deepen our understanding of the interplay among rings, modules, and graphs.展开更多
A black ring is an asymptotically fiat vacuum solution of the n-dimensional Einstein equations with an event horizon of topology S1× Sn-3. In this study, a connection between the black ring entropy and the Weyl t...A black ring is an asymptotically fiat vacuum solution of the n-dimensional Einstein equations with an event horizon of topology S1× Sn-3. In this study, a connection between the black ring entropy and the Weyl tensor Cμνλρ is explored by interpreting the Weyl scalar invariant CμνλρCμνλρ as the entropy density in five-dimensional space-time. It is shown that the proper volume integral of CμνλρCμνλρfor a neutral black ring is proportional to the black ring entropy in the thin-ring limit. Similar calculations are extended to more general cases： a black string, a black ring with two angular momenta, and a black ring with a cosmological constant. The proportionality is also found to be valid for these complex black objects at the leading order.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.62073087,61973087 and 61973090)the Key-Area Research and Development Program of Guangdong Province(Grant No.2019B010154002)。
文摘Nonnegative tensor ring(NTR) decomposition is a powerful tool for capturing the significant features of tensor objects while preserving the multi-linear structure of tensor data. The existing algorithms rely on frequent reshaping and permutation operations in the optimization process and use a shrinking step size or projection techniques to ensure core tensor nonnegativity, which leads to a slow convergence rate, especially for large-scale problems. In this paper, we first propose an NTR algorithm based on the modulus method(NTR-MM), which constrains core tensor nonnegativity by modulus transformation. Second, a low-rank approximation(LRA) is introduced to NTR-MM(named LRA-NTR-MM), which not only reduces the computational complexity of NTR-MM significantly but also suppresses the noise. The simulation results demonstrate that the proposed LRA-NTR-MM algorithm achieves higher computational efficiency than the state-of-the-art algorithms while preserving the effectiveness of feature extraction.
文摘This paper investigates the connections between ring theory, module theory, and graph theory through the graph G(R)of a ring R. We establish that vertices of G(R)correspond to modules, with edges defined by the vanishing of their tensor product. Key results include the graph’s connectivity, a diameter of at most 3, and a girth of at most 7 when cycles are present. We show that the set of modules S(R)is empty if and only if R is a field, and that for semisimple rings, the diameter is at most 2. The paper also discusses module isomorphisms over subrings and localization, as well as the inclusion of G(T)within G(R)for a quotient ring T, highlighting that the reverse inclusion is not guaranteed. Finally, we provide an example illustrating that a non-finitely generated module M does not imply M⊗M=0. These findings deepen our understanding of the interplay among rings, modules, and graphs.
文摘A black ring is an asymptotically fiat vacuum solution of the n-dimensional Einstein equations with an event horizon of topology S1× Sn-3. In this study, a connection between the black ring entropy and the Weyl tensor Cμνλρ is explored by interpreting the Weyl scalar invariant CμνλρCμνλρ as the entropy density in five-dimensional space-time. It is shown that the proper volume integral of CμνλρCμνλρfor a neutral black ring is proportional to the black ring entropy in the thin-ring limit. Similar calculations are extended to more general cases： a black string, a black ring with two angular momenta, and a black ring with a cosmological constant. The proportionality is also found to be valid for these complex black objects at the leading order.
