130 research outputs found
A Note on Commutative Gelfand Theory for Real Banach Algebras
Pfaffenberger and Phillips [2] consider a real and unital case of the classical commutative Gelfand theorem and obtain two representation theorems. One is to represent a unital real commutative Banach algebra A as an algebra of continuous functions on the unital homomorphism space ΦA. The other is to represent A as an algebra of continuous sections on the maximal ideal space MA. In this note, we point out that similar theorems for non-unital case hold and show that two representation theorems are essentially identical.</p
A perturbation of ring derivations on Banach algebras
AbstractSuppose A is a Banach algebra and suppose f:A→A is an approximate ring derivation in the sense of Hyers–Ulam–Rassias. This stability phenomenon was introduced for the first time in the subject of functional equations by Th.M. Rassias [Th.M. Rassias, On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc. 72 (1978) 297–300]. If A has an approximate identity, or if A is semisimple and commutative, then we prove that f is an exact ring derivation
A Classification of Two-dimensional Endo-commutative Algebras over F_2
We introduce a new class of algebras called endo-commutative algebras in
which the square mapping preserves multiplication, and provide a complete
classification of endo-commutative algebras of dimension 2 over the field F_2
of two elements. We list all multiplication tables of the algebras up to
isomorphism. This clarifies the difference between commutativity and
endo-commutativity of algebras.Comment: 19 page
A classification of 2-dimensional endo-commutative straight algebras of rank 1 over a non-trivial field
An endo-commutative algebra is a nonassociative algebra in which the square
mapping preserves multiplication. In this paper, we give a complete
classification of 2-dimensional endo-commutative straight algebras of rank one
over an arbitrary non-trivial field, where a straight algebra of dimension 2
satisfies the condition that there exists an element such that and
are linearly independent. We list all multiplication tables of the
algebras up to isomorphism.Comment: 10 pages. arXiv admin note: text overlap with arXiv:2304.1251
An extension of Helson-Edwards theorem to Banach Modules
An extension of the Helson-Edwards theorem for the group algebras to Banach
modules over commutative Banach algebras is given. This extension can be viewed as a
generalization of Liu-Rooij-Wang's result for Banach modules over the group algebras
Classification of Zeropotent Algebras of Dimension 3 over (Logic, Language, Algebraic system and Related Areas in Computer Science)
This is a summary of our results [Y. Kobayashi, K. Shirayanagi, S.-E. Takahasi and M. Tsukada, Classification of three-dimensional zeropotent algebras over an algebraically closed field, Comm. Algebra, Vol. 45 (12), 5037-5052, 2017.] and [K. Shirayanagi, S.-E. Takahasi, M. Tsukada and Y. Kobayashi, Classification of three-dimensional zeropotent algebras over the real number field, Comm. Algebra, Vol. 46 (11), 4665-4681, 2018.]
A note on finite codimensional linear isometries of C
Let (X,Y) be a pair of compact Hausdorff spaces. It is shown that a certain
property of the class of continuous maps of Y onto X is equivalent to the non-existence of linear
isometry of C(X) into C(Y) whose range has finite codimension >0
Continuously differentiable means
The Eurozone crisis and the refugee crisis are showcases of the problems associated with the EU's shift from market integration to the integration of core state powers. The integration of core state powers responds to similar demand factors as market integration (interdependence, externalities and spillover) but its supply is more tightly constrained by a high propensity for zero‐sum conflict, a functional requirement for centralized fiscal, coercive and administrative capacities, and high political salience. We show how these constraints structured the initial design of Economic and Monetary Union and of Schengen, made them vulnerable to crisis, and shaped policy options during the crises: they made horizontal differentiation unattractive, re‐regulation ineffective, centralized risk and burden‐sharing unfeasible, and the externalization of adjustment burdens to non‐EU actors necessary by default. In conclusion, we explore possible escape routes from the trap
Significance and Teaching Methods of Integration Constants
多くの教科書では不定積分の公式を掲げるが,紙面の都合の為か積分定数を省略する事が多い。これが為か学生達は積分定数について曖昧だったり,軽視する傾向にある。本論は具体的な例を挙げ,積分定数の意義と大切さ,その指導法について述べる。指導法・実践報
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