scholarly journals On quaternionic functional analysis

2007 ◽  
Vol 143 (2) ◽  
pp. 391-406 ◽  
Author(s):  
CHI-KEUNG NG
Keyword(s):  
Functional Analysis ◽  
Hilbert Spaces ◽  
Representation Theorem ◽  
Vector Spaces ◽  
Riesz Representation Theorem ◽  
Real Vector ◽  
Riesz Representation

AbstractIn this paper, we will show that the category of quaternion vector spaces, the category of (both one-sided and two sided) quaternion Hilbert spaces and the category of quaternion B*-algebras are equivalent to the category of real vector spaces, the category of real Hilbert spaces and the category of real C*-algebras respectively. We will also give a Riesz representation theorem for quaternion Hilbert spaces and will extend the main results in [12] (namely, we will give the full versions of the Gelfand–Naimark theorem and the Gelfand theorem for quaternion B*-algebras). On our way to these results, we compare, clarify and unify the term ‘quaternion Hilbert spaces’ in the literatures.

ON THE RIESZ REPRESENTATION THEOREM IN TOPOLOGICAL VECTOR SPACES

2000 ◽  
Vol 36 (3-4) ◽  
pp. 347-352
Author(s):  
M. A. Alghamdi ◽  
L. A. Khan ◽  
H. A. S. Abujabal
Keyword(s):  
Representation Theorem ◽  
Type Theorem ◽  
Representation Type ◽  
Vector Spaces ◽  
Riesz Representation Theorem ◽  
Topological Vector Spaces ◽  
Riesz Representation

I this paper we establish a Riesz representation type theorem which characterizes the dual of the space C rc (X,E)endowed with the countable-ope topologyi the case of E ot ecessarilya locallyconvex TVS.

Hilbert Spaces

2021 ◽  
pp. 290-340
Author(s):  
Adel N. Boules
Keyword(s):  
Hilbert Spaces ◽  
Representation Theorem ◽  
Compact Operators ◽  
Projection Operators ◽  
Riesz Representation Theorem ◽  
Introductory Course ◽  
Normal Operators ◽  
Riesz Representation ◽  
Alternative Approaches

This chapter is a good introduction to Hilbert spaces and the elements of operator theory. The two leading sections contains staple topics such as the projection theorem, projection operators, the Riesz representation theorem, Bessel’s inequality, and the characterization of separable Hilbert spaces. Sections 7.3 and 7.4 contain a rather detailed study of self-adjoint and compact operators. Among the highlights are the Fredholm theory and the spectral theorems for compact self-adjoint and normal operators, with applications to integral equations. The section exercises contain problems that suggest alternative approaches, thus allowing the instructor to shorten the chapter while preserving good depth. The last section extends the results to compact operators on Banach spaces. The chapter contains more results than is typically found in an introductory course.

scholarly journals The Orthogonal Projection and the Riesz Representation Theorem

2015 ◽  
Vol 23 (3) ◽  
pp. 243-252
Author(s):  
Keiko Narita ◽  
Noboru Endou ◽  
Yasunari Shidama
Keyword(s):  
Hilbert Spaces ◽  
Orthogonal Projection ◽  
Representation Theorem ◽  
Final Section ◽  
Riesz Representation Theorem ◽  
Linear Functionals ◽  
Normed Spaces ◽  
Bounded Linear ◽  
Riesz Representation ◽  
Equivalent Properties

Abstract In this article, the orthogonal projection and the Riesz representation theorem are mainly formalized. In the first section, we defined the norm of elements on real Hilbert spaces, and defined Mizar functor RUSp2RNSp, real normed spaces as real Hilbert spaces. By this definition, we regarded sequences of real Hilbert spaces as sequences of real normed spaces, and proved some properties of real Hilbert spaces. Furthermore, we defined the continuity and the Lipschitz the continuity of functionals on real Hilbert spaces. Referring to the article [15], we also defined some definitions on real Hilbert spaces and proved some theorems for defining dual spaces of real Hilbert spaces. As to the properties of all definitions, we proved that they are equivalent properties of functionals on real normed spaces. In Sec. 2, by the definitions [11], we showed properties of the orthogonal complement. Then we proved theorems on the orthogonal decomposition of elements of real Hilbert spaces. They are the last two theorems of existence and uniqueness. In the third and final section, we defined the kernel of linear functionals on real Hilbert spaces. By the last three theorems, we showed the Riesz representation theorem, existence, uniqueness, and the property of the norm of bounded linear functionals on real Hilbert spaces. We referred to [36], [9], [24] and [3] in the formalization.

Yet another short proof of the Riesz representation theorem

1989 ◽  
Vol 105 (1) ◽  
pp. 139-140 ◽  
Author(s):  
David Ross
Keyword(s):  
Representation Theorem ◽  
Short Proof ◽  
Riesz Representation Theorem ◽  
Riesz Theorem ◽  
Riesz Representation

F. Riesz's ‘Representation Theorem’ has been proved by methods classical [11, 12], category-theoretic [7], and functional-analytic [2, 9]. (Garling's remarkable proofs [5, 6] owe their brevity to the combined strength of these and other methods.) These proofs often reveal a connection between the Riesz theorem and some unexpected area of mathematics.

A nonstandard proof of the Riesz representation theorem for weakly compact operators on C(Ω)

1989 ◽  
Vol 105 (1) ◽  
pp. 141-145
Author(s):  
Yeneng Sun
Keyword(s):  
Representation Theorem ◽  
Compact Operators ◽  
Riesz Representation Theorem ◽  
Linear Functionals ◽  
Weakly Compact ◽  
Vector Measures ◽  
Riesz Representation ◽  
Weakly Compact Operators ◽  
Measure Technique

AbstractAn easy way to construct the representing vector measures of weakly compact operators on C(Ω) is given by using the Loeb measure technique. This construction is not based on the Riesz representation theorem for linear functionals; thus we have a uniform way to treat the scalar and vector cases. Also the star finite representations of regular vector measures follow from the proof.

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