Auflistung Mathematics nach Titel
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Vulićević, Branko (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/221 Dateien zu dieser Ressource: 1
phdBVulicevic.pdf ( 3.445Mb ) -
Savić, Vladimir (Belgrade)[more][less]
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Ivić, Aleksandar (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/307 Dateien zu dieser Ressource: 1
phdAleksandarIvic.pdf ( 2.440Mb ) -
Đoković, Dragomir (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/143 Dateien zu dieser Ressource: 1
phdDragomirDjokovic.pdf ( 2.776Mb ) -
Lazić, Milivoje (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/262 Dateien zu dieser Ressource: 1
phdMilivojeLazic.pdf ( 7.986Mb ) -
Stanojević, Momir (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/351 Dateien zu dieser Ressource: 1
phdMomirStanojevic.pdf ( 2.713Mb ) -
Jojić, Duško (Belgrade , 2005)[more][less]
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Cana, Mazllum (Pristina , 1977)[more][less]
URI: http://hdl.handle.net/123456789/54 Dateien zu dieser Ressource: 1
phdMazllumCana.pdf ( 2.167Mb ) -
Milovančević, Dušan (Belgrade , 1982)[more][less]
URI: http://hdl.handle.net/123456789/42 Dateien zu dieser Ressource: 1
phdDusanMilovancevic.pdf ( 2.085Mb ) -
Martinović, Milan (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/59 Dateien zu dieser Ressource: 1
phdMilanMartinovic.pdf ( 4.770Mb ) -
Milošević, Radivoje (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/311 Dateien zu dieser Ressource: 1
phdRadivojeMilosevic.pdf ( 8.536Mb ) -
Pilipović, Stevan (Novi Sad)[more][less]
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Ašić, Miroslav (Belgrade)[more][less]
URI: http://hdl.handle.net/123456789/349 Dateien zu dieser Ressource: 1
phdMiroslavAsic.pdf ( 4.813Mb ) -
Milovanović, Zorica (Beograd , 2015)[more][less]
Zusammenfassung: U primenama, naro cito u in zenjerstvu, cesto se sre cu kompozitne ili slojevite strukture, pri cemu se osobine pojedinih slojeva mogu zna cajno razlikovati od osobina okolnog materijala. Slojevi mogu imati strukturnu, termi cku, elektromagnetsku ili opti cku ulogu itd. Matemati ckim modelovanjem prenosa energije i mase u oblastima sa slojevima dobijaju se tzv. transmisioni problemi. Na samom po cetku, u disertaciji se razmatra transmisioni spektralni problem u oblasti koja se sastoji od dva disjunktna intervala. Na svakom intervalu zadat je problem sopstvenih vrednosti, dok se interakcija izmed u njihovih re senja opisuje nelokalnim uslovima saglasnosti. Dokazana je egzistencija prebrojivog niza generalisanih re senja, pri cemu ured eni parovi sopstvenih funkcija pripadaju odgovaraju cim prostorima Soboljeva. Opisana je struktura spektra i asimptotsko pona sanje sopstvenih vrednosti. Konstruisana je diferencijska shema za njihovo re savanje. Pored transmisionog spektralnog problema, u disertaciji se razmatraju klase nestandardnih elipti ckih i paraboli ckih transmisionih problema u disjunktnim oblastima. Kao modelni primer uzeta je oblast koja se sastoji iz dva nesusedna pravougaonika. U svakoj podoblasti zadat je grani cni problem elipti ckog tipa, odnosno po cetnograni cni problem paraboli ckog tipa. Interakcija izmed u re senja opisuje se pomo cu nelokalnih uslova saglasnosti na granicama posmatranih podoblasti. Razmotreno je vi se primera zi ckih i in zenjerskih zadataka koji se svode na transmisione probleme sli cnog tipa. Za modelne probleme dokazana je egzistencija i jedinstvenost re senja u odgovaraju cim prostorima Soboljeva. Takod e su konstruisane diferencijske sheme za njihovo re URI: http://hdl.handle.net/123456789/3999 Dateien zu dieser Ressource: 1
phdZoricaMilovanovic.pdf ( 8.476Mb ) -
Isaković-Ilić, Mirjana (Belgrade)[more][less]
Zusammenfassung: In this thesis cut elimination and decidability for several propositional substructural logics are studied. The thesis consists of nine chapters. Chapters 2-6 make the first part of the thesis. In that part sequent systems for substrictural logics are formulated. In Chapters 3 and 4 for each of these systems an algebraic structure is given and completeness and consistency are proved. In Chapters 5 and 6 cut elimination and decidability for these systems are studied. It is well known that sequent system of classical Lambek logic, the system SL is decidable and that cut is not an admissible rule in CL. Another sequent system for classical Lambek logic, the system CL* is formulated, and the elimination of cut in CL* is proved. The system CL* does not posses the subformula property, so decidability for classical Lambek logic is not the direct consequence of the cut-elimination procedure in CL*. However, on the basis of the cut elimination procedure in CL*, a procedure for deciding of whether a sequent is provable in CL* or not is given (i. e., a new (pure syntactic) proof of decidability for classical Lambek logic is given). The same result is shown for classical Lambek logic with weakening. In the second part of the thesis (chapters 7-9), by using that proof, an algorithm (based on the tableau method) is formulated for deciding whether or not a formula is the theorem in any of considered substructural logics. URI: http://hdl.handle.net/123456789/201 Dateien zu dieser Ressource: 1
phdMirjanaIsakovicIlic.pdf ( 1.047Mb ) -
Mosurović, Milenko (Belgrade)[more][less]
Zusammenfassung: The results of this thesis are connected with papers of Wolter and Zakharyashchev in which various expressive and decidable description logics with epistemic, temporal, and dynamic operators are constructed, but the complexity of the satisfaction problem in these logics has remained unclear. The thesis consists of seven chapters. Chapter 1 and 5 contain the notions and properties which are used in other chapters. In Chapter 2 a fragment of the logic DIF, which is called D_1IF , is considered and new constructions and proofs for that logic are given. In Chapter 3 a fragment of the logic DIO, which is called D_1IO, is studied. In Chapter 4 by using the results from Chapter 2 and Chapter 3 NEXPTIME algorithm, which tests whether a structure simple quasi-world or not, is constructed and it is used in Chapter 7. In Chapters 6 and 7 it is shown that the modal description logics of Wolter and Zakharyashchev based on arbitrary frames are NEXPTIME-complete, no matter whether the underlying description logic is ALC, CI or C_1IQ. Moreover, it is shown that these logics based on S5-frames (for knowledge), and KD45-frames (for beliefs) are also NEXPTIME-complete. Finally, the following property is shown: the description logics of Wolter and Zakharyashchev based on N-frames (for time) are EXPSPACE-complete, no matter whether the underlying description logic is ALC_U, CI_U or C_1IQ_U. URI: http://hdl.handle.net/123456789/192 Dateien zu dieser Ressource: 1
phdMilenkoMosurovic.pdf ( 3.024Mb ) -
Kanan, Asmaa (Beograd , 2013)[more][less]
Zusammenfassung: Semiring with zero and identity is an algebraic structure which generalizes a ring. Namely, while a ring under addition is a group, a semiring is only a monoid. The lack of substraction makes this structure far more difficult for investigation than a ring. The subject of investigation in this thesis are matrices over commutative semirings (wiht zero and identity). Motivation for this study is contained in an attempt to determine which properties for matrices over commutative rings may be extended to matrices over commutative semirings, and, also, which is closely connected to this question, how can the properties of modules over rings be extended to semimodules over semirings. One may distinguish three types of the obtained results. First, the known results concerning dimension of spaces of n-tuples of elements from a semiring are extended to a new class of semirings from the known ones until now, and some errors from a paper by other authors are corrected. This question is closely related to the question of invertibility of matrices over semirings. Second type of results concerns investigation of zero divisors in a semiring of all matrices over commutative semirings, in particular for a class of inverse semirings (which are those semirings for which there exists some sort of a generalized inverse with respect to addition). Because of the lack of substraction, one cannot use the determinant, as in the case of matrices over commutative semirings, but, because of the fact that the semirings in question are inverse semirings, it is possible to define some sort of determinant in this case, which allows the formulation of corresponding results in this case. It is interesting that for a class of matrices for which the results are obtained, left and right zero divisors may differ, which is not the case for commutative rings. The third type of results is about the question of introducing a new rank for matrices over commutative semirings. For such matrices, there already exists a number of rank functions, generalizing the rank function for matrices over fields. In this thesis, a new rank function is proposed, which is based on the permanent, which is possible to define for semirings, unlike the determinant, and which has good enough properties to allow a definition of rank in such a way. URI: http://hdl.handle.net/123456789/4274 Dateien zu dieser Ressource: 1
phdKanan_Asmaa.pdf ( 1.221Mb ) -
Dedagić, Fehim (Priština)[more][less]
URI: http://hdl.handle.net/123456789/43 Dateien zu dieser Ressource: 1
phdFehimDedagic.pdf ( 2.250Mb ) -
Karapetrović, Boban (Beograd , 2017)[more][less]
Zusammenfassung: In this thesis, we study the in nite Hilbert matrix viewed as an operator, called the Hilbert matrix operator and denoted by H and Libera operator, denoted by L, on the classical spaces of holomorphic functions on the unit disk in the complex plane. It is well known that the Hilbert matrix operator H is a bounded operator from the Bergman space Ap into Ap if and only if 2 < p < 1. Also, it is known that the norm of the Hilbert matrix operator H on the Bergman space Ap is equal sin 2 p , when 4 p < 1, and it was conjectured that kHkAp!Ap = sin 2 p ; when 2 < p < 4. In this thesis we prove this conjecture. We nd the lower bound for the norm of the Hilbert matrix operator H on the weighted Bergman space Ap; , kHkAp; !Ap; sin ( +2) p ; for 1 < + 2 < p: We show that if 4 2( + 2) p, then kHkAp; !Ap; = sin ( +2) p ; while in the case 2 +2 < p < 2( +2), upper bound for the norm kHkAp; !Ap; , better then known, is obtained. We prove that the Hilbert matrix operator H is bounded on the Besov spaces Hp;q; if and only if 0 < p; ; = 1 p + 1 < 1. In particular, operator H is bounded on the Bergman space Ap; if and only if 1 < + 2 < p and it is bounded on the Dirichlet space Dp = Ap; 1 if and only if maxf1; p 2g < < 2p 2. We also show that if > 2 and 0 < " 2, then the logarithmically weighted Bergman space A2 log is mapped by the Hilbert matrix operator H into the space A2 log 2" . If 2 R, then the Hilbert matrix operator H maps logarithmically weighted Bloch space Blog into Blog +1. We also prove that operator H maps logarithmically weighted Hardy-Bloch space B1 log , when 0, into B1 log 1 and that this result is sharp. Also, we have that the space VMOA is not mapped by the Hilbert matrix operator H into the Bloch space B. On the other hand, we nd that the Libera operator L is bounded on the Besov space Hp;q; if and only if 0 < p; ; = 1 p + 1. Then, we prove that if > 1, then the logarithmically weighted Bergman space A2 log is mapped by the Libera operator L into the space A2 log 1 , while if 2 R, then the Libera operator L maps logarithmically weighted Bloch space Blog into itself. If > 0, we have that operator L maps logarithmically weighted Hardy-Bloch space B1 log into B1 log 1 and we show that this result is sharp. The well known conjecture due to Korenblum about maximum principle in Bergman space Ap states: Let 0 < p < 1. Then there exists a constant 0 < c < 1 with the following property. If f and g are holomorphic functions in the unit disk D, such that jf(z)j jg(z)j for all c < jzj < 1, then kfkAp kgkAp . Hayman proved Korenblum's conjecture for p = 2 and Hinkkanen generalized this result, by proving conjecture for all 1 p < 1. The case 0 < p < 1 of conjecture still remains open. In this thesis we resolve this case of the Korenblum's conjecture, by proving that Korenblum's maximum principle in Bergman space Ap does not hold when 0 < p < 1. URI: http://hdl.handle.net/123456789/4497 Dateien zu dieser Ressource: 1
Boban_Karapetrovic_doktorska_disertacija.pdf ( 1.392Mb ) -
Ivković, Zoran (Belgrade , 1964)[more][less]
URI: http://hdl.handle.net/123456789/216 Dateien zu dieser Ressource: 1
phdZoranIvkovic.pdf ( 1.731Mb )