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Abstract: V doktorski disertaciji si bomo v uvodu ogledali nekaj osnovnih pojmov, definicij ter pomembnejših rezultatov s področja algebre. Obravnavali bomo funkcionalne enačbe, ki so v zvezi z odvajanji, centralizatorji ter sorodnimi preslikavami na prakolobarjih, polprakolobarjih in standardnih operatorskih algebrah. Na tem področju že vrsto let delujejo tudi slovenski matematiki, ki so s svojimi rezultati pomembno vplivali na razvoj tega področja. Že v osemdesetih letih sta bila močno dejavna na tem področju J. Vukman, M. Brešar, sledili pa so B. Zalar, B. Hvala, v novejšem času pa M. Fošner, I. Kosi-Ulbl, D. Benkovič, D. Eremita, A. Fošner, N. Peršin ter N. Širovnik. Osnovno sredstvo pri reševanju funkcionalnih enačb, ki bodo predstavljene v disertaciji, je teorija funkcijskih identitet, ki jo je leta 2000 v cite{87} predstavil M. Brešar. Leta 2007 pa so jo M. Brešar, M. A. Chebotar in W. S. Martindale III tudi podrobneje predstavili v knjigi cite{MB4}. Teorija funkcijskih identitiet bo v disertaciji predstavljena skupaj s polinomskimi identitietami ter d-prostimi množicami.
Keywords: Aditivna preslikava, linearen operator, odvajanje, jordansko odvajanje, jordansko trojno odvajanje, centralizator, funkcionalna enačba, standardna operatorska algebra, prakolobar, polprakolobar, Banachov prostor, involucija.
Published in DKUM: 21.10.2016; Views: 2278; Downloads: 146
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Abstract: In this paper functional equations related to derivations on semiprime rings and standard operator algebras are investigated. We prove, for example, the following result, which is related to a classical result of Chernoff. Let ▫$X$▫ be a real or complex Banach space, let ▫$L(X)$▫ be the algebra of all bounded linear operators of ▫$X$▫ into itself and let ▫$A(X) subset L(X)$▫ be a standard operator algebra. Suppose there exist linear mappings ▫$D,G colon A(X) to L(X)$▫ satisfying the relations ▫$D(A^3)=D(A^2)A + A^2G(A)$▫, ▫$G(A^3) = G(A^2)A + A^2D(A)$▫ for all ▫$A in A(X)$▫. In this case there exists ▫$B in L(X)$▫ such that ▫$D(A) = G(A) = [A,B]$▫ holds for all ▫$A in A(X)$▫.
Keywords: matematika, algebra, prakolobar, polprakolobar, Banachov prostor, standardna operatorska algebra, odvajanje, jordansko odvajanje, jordansko trojno odvajanje, mathematics, algebra, prime ring, semiprime ring, Banach space, standard operator algebra, derivation, Jordan derivation, Jordan triple derivation
Published in DKUM: 10.07.2015; Views: 1479; Downloads: 68
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Abstract: The purpose of this paper is to prove the following result. Let ▫$m ge 1$▫, ▫$n ge 1$▫ be some fixed integers and let ▫$R$▫ be a prime ring with ▫$text{char}(R)= 0$▫ or ▫$(m+n)^2 < text{char}(R)$▫. Suppose there exists an additive mapping ▫$T colon R to R$▫ satisfying the relation ▫$2(m+n)^2T(x^3) = m(2m+n)T(x)x^2 + 2mnxT(x)x + n(2n+m)x^2T(x)$▫ for all ▫$x in R$▫. In this case ▫$T$▫ is a two-sided centralizer.
Keywords: matematika, algebra, kolobar, prakolobar, polprakolobar, Banachov prostor, Hilbertov prostor, algebra vseh omejenih linearnih operatorjev, standardna operatorska algebra, odvajanje, jordansko odvajanje, centralizator, algebra, ring, prime ring, semiprime ring, Banach space, Hilbert space, algebra of all bounded linear operators, standard operator algebra, derivation, Jordan derivation, left (right) centralizer, two-sided centralizer, left (right) Jordan centralizer, (m, n)-Jordan centralizer
Published in DKUM: 10.07.2015; Views: 1422; Downloads: 139
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Abstract: Naj bosta ▫$A$▫ in ▫$B$▫ ▫$C^ast$▫-algebri, ▫$X$▫ naj bo bistveni Banachov ▫$A$▫-bimodul in naj bosta ▫$T colon A to B$▫ in ▫$S colon A to X$▫ zvezni linearni preslikavi; ▫$T$▫ naj bo surjektivna. Denimo, da je ▫$T(a)T(b) + T(b)T(a) = 0$▫ in ▫$S(a)b + bS(a) + aS(b) + S(b)a = 0$▫, kadarkoli ▫$a, b in A$▫ zadoščata ▫$ab = ba = 0$▫. Dokažemo, da je ▫$T = wPhi$▫ in ▫$S = D + wPsi$▫, kjer ▫$w$▫ leži v centru multiplikatorske algebre ▫$B$▫, ▫$Phicolon A to B$▫ je jordanski epimorfizem, ▫$D colon A to X$▫ je odvajanje in ▫$Psi colon A to X$▫ je bimodulski homomorfizem.
Keywords: matematika, teorija operatorjev, ▫$C^ast$▫-algebra, homomorfizem, jordanski homomorfizem, odvajanje, jordansko odvajanje, ohranjevalec ničelnega produkta, mathematics, operator theory, ▫$C^ast$▫-algebra, homomorphism, Jordan homomorphism, derivation, Jordan derivation, zero-product-preserving map
Published in DKUM: 10.07.2015; Views: 1114; Downloads: 47
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Abstract: Naj bo ▫$H$▫ kompleksni Hilbertov prostor, ▫$mathcal{B}(H)$▫ algebra vseh omejenih linearnih operatorjev na ▫$H$▫ ter ▫$mathcal{A}(H)$▫ standardna operatorska algebra, zaprta za adjungiranje. Če je ▫$T: mathcal{A}(H) to mathcal{B}(H)$▫ linearna preslikava, ki zadošča identiteti ▫$T(AA^ast A) = T(A)A^ast A - AT(A^ast)A + AA^ast T(A)$▫ za vsak ▫$A$▫ iz ▫$mathcal{A}(H)$▫, potem je ▫$T(A) = AB + BA$▫ za vsak ▫$A$▫ iz A(H), kjer je ▫$B$▫ operator iz ▫$mathcal{B}(H)$▫.
Keywords: matematika, algebra, kolobar, prakolobar, polprakolobar, Banachov prostor, Hilbertov prostor, standardna operatorska algebra, odvajanje, jordansko odvajanje, bicirkularni projektor, mathematics, algebra, ring, ▫$^ast$▫-ring, prime ring, semiprime ring, Banach space, Hilbert space, standard operator algebra, derivation, Jordan derivation, bicircular projection
Published in DKUM: 10.07.2015; Views: 1406; Downloads: 98
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