Results 131 to 140 of about 382 (168)

Theorems of Idempotent Commutative Groupoids

Algebra Colloquium, 2005
In this paper, among other results, we prove that a clone C with five essentially binary operations is minimal if and only if C is a clone of a non-trivial affine space over GF(7). This result is a product of systematic investigation of varieties of idempotent commutative groupoids.
Dudek, J., Gałuszka, J.
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A Generalized Commutativity Theorem

Zeitschrift für Analysis und ihre Anwendungen, 1991
Summary: Let \(H\) be a complex separable Hilbert space, \({\mathcal C}\) the class of contractions with \(C_{\cdot 0}\) completely non-unitary parts, \({\mathcal C}_ 0\) the class of \(A\in {\mathcal C}\) which satisfy the property (called property (P2)) that if the restriction of \(A\) to an invariant subspace \(M\) is normal, then \(M\) reduces \(A\)
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Opechowskis theorem and commutator groups

Journal of Physics A: Mathematical and General, 1986
Given the definition of the double point groups, \textit{W. Opechowski} [Physica 7, 552-562 (1940; Zbl 0023.30201)] proved that if a finite group \({\mathcal G}\) as a subgroup of the three-dimensional rotation group \({\mathcal S}{\mathcal O}(2)\), possesses two rotations by angle \(\pi\) around two mutually perpendicular axes, then the number of ...
Caride, A. O., Zanette, S. I.
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Non-Commutative Fejér Theorems

Integral Equations and Operator Theory, 2012
The author of the paper under review studies the problem of approximation of operators in the uniform Roe algebra \(C^{*}_u(G)\) by their truncations. Here, \(G\) is a finitely generated group. In particular, sufficient conditions for such approximability are obtained.
Chen, Xiaoman, Fu, Benyin
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Commutativity Theorems for Rings with Constraints Involving a Commutative Subset

Results in Mathematics, 1987
Let R denote a ring. Let A be a commutative subset containing all elements of R with square 0; let E be the set of idempotents of R; let \(q>1\) be an integer. The first theorem asserts that R must be commutative if it has the following two properties: (i) if x,y\(\in R\) and x-y\(\in A\), then \(x^ q=y^ q\) or x and y both centralize A; (ii) \(R ...
Tominaga, Hisao, Yaqub, Adil
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A Commutativity Theorem for Rings with Involution

Canadian Journal of Mathematics, 1978
A ring with involution R is an associative ring endowed with an antiautomorphism * of period 2. One of the first commutativity results for rings with * is a theorem of S. Montgomery asserting that if R is a prime ring, in which every symmetric element s = s* is of the form s — sn(s) (n(s) ≧ 2), then either R is commutative or R is the 2 X 2 matrices ...
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Commutativity theorems for s-unital rings with constraints on commutators

Results in Mathematics, 1992
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Abujabal, Hamza A. S., Perić, Veselin
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Differential invariants: theorem of commutativity

Communications in Nonlinear Science and Numerical Simulation, 2004
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The Commutation’s Theorem

2011
We show that for a locally compact unimodular group G, every T e CV 2(G) is the limit of convolution operators associated to bounded measures.
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The Commutant Lifting Theorem

1990
In this chapter we will introduce the main theorem of this monograph, namely, the Commutant Lifting Theorem and we will give several different proofs for it. Each proof illuminates different features of this theorem. We also use the second proof to discuss the uniqueness question in the commutant lifting theorem.
Ciprian Foias, Arthur E. Frazho
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