Chansangiam, Pattrawut
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Preferred name
Chansangiam, Pattrawut
Alternative Name
Chansangiam, P.
Main Affiliation
Email
pattrawut.ch@kmitl.ac.th
5 results
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Item type:Publication, Analytic properties of tracy-singh products for operator matrices(2018-01-01); Lewkeeratiyutkul, WicharnWe show that the Tracy-Singh product of Hilbert space operators is continuous with respect to the operator-norm topology. The Tracy-Singh product of two nonzero operators is compact if and only if both factors are compact. We provide upper and lower bounds for certain Schatten p-norms of the Tracy-Singh product of operators. It turns out that this product is continuous with respect to the topologies on norm ideals of compact operators, trace class operators, and Hilbert-Schmidt class operators. Thus the Tracy-Singh product preserves such classes of operators. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Algebraic and order properties of tracy-singh products for operator matrices(2018-01-01); Lewkeeratiyutkul, WicharnWe generalize the tensor product for operators to the Tracy-Singh product for operator matrices acting on the direct sum of Hilbert spaces. This kind of operator product is compatible with algebraic operations and order relations for operators. It follows that this product preserves many structure properties of operators. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Operator connections and Borel measures on the unit interval(2015-08-01); Lewkeeratiyutkul, WicharnA connection is a binary operation for positive operators satisfying monotonicity, the transformer inequality, and joint-continuity from above. A normalized connection is called a mean. Here we show that there is a one-to-one correspondence between connections and finite Borel measures on the unit interval via the integral representation in terms of weighted harmonic means with respect to that measure. This correspondence is affine and order-preserving. Hence every mean can be regarded as an average of weighted harmonic means. We also investigate decompositions of connections, means, symmetric connections and symmetric means. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Convergence analysis of gradient-based iterative algorithms for a class of rectangular Sylvester matrix equations based on Banach contraction principle(2021-12-01); Lewkeeratiyutkul, WicharnWe derive an iterative procedure for solving a generalized Sylvester matrix equation AXB+ CXD= E, where A, B, C, D, E are conforming rectangular matrices. Our algorithm is based on gradients and hierarchical identification principle. We convert the matrix iteration process to a first-order linear difference vector equation with matrix coefficient. The Banach contraction principle reveals that the sequence of approximated solutions converges to the exact solution for any initial matrix if and only if the convergence factor belongs to an open interval. The contraction principle also gives the convergence rate and the error analysis, governed by the spectral radius of the associated iteration matrix. We obtain the fastest convergence factor so that the spectral radius of the iteration matrix is minimized. In particular, we obtain iterative algorithms for the matrix equation AXB= C, the Sylvester equation, and the Kalman–Yakubovich equation. We give numerical experiments of the proposed algorithm to illustrate its applicability, effectiveness, and efficiency. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Tracy-singh products and classes of operators(2019-07-01); Lewkeeratiyutkul, WicharnWe investigate relationship between Tracy-Singh products and certain classes of Hilbert space operators. We show that the normality, hyponormality, paranormality of operators are preserved by Tracy-Singh products. Operators of class-A type are also preserved under Tracy-Singh products. Moreover, we obtain necessary and sufficient conditions for the Tracy- Singh product of two operators to be normal, quasinormal, (co)isometry, and unitary.