30 results
Search Results
Now showing 1 - 10 of 30
Article Transmission Eigenvalues Problem of a Schrödinger Equation(Tubitak Scientific & Technological Research Council Turkey, 2024) Yıldırım, Emel; Baıramov, ElgizIn this paper, transmission eigenvalues of a Schrödinger equation have been studied by constructing a new inner product and using Weyl theory. Necessary conditions for these eigenvalues to be negative, real, and finite have been examined. This method has provided a new framework related to transmission eigenvalue problems and the investigation of their properties. The conclusions have been verified for the special case of the problem.Article An Integrated Intuitionistic Fuzzy Multi Criteria Decision Making Method for Facility Location Selection(2011) Boran, Fatih EmreThe facility location selection, which is one of the important activities in strategic planning for a wide range of private and public companies, is a multi-criteria decision making problem including both quantitative and qualitative criteria. Traditional methods for facility location selection can not be effectively handled because information can not be represented by precise information under many conditions. This paper proposes the integration of intuitionistic fuzzy preference relation aiming to obtain weights of criteria and intuitionistic fuzzy TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method aiming to rank alternatives for dealing with imprecise information on selecting the most desirable facility location. To illustrate the application of the proposed method, a practical application is given.Article An Exhaustive Computer Search for Finding New Curves With Many Points Among Fibre Products of Two Kummer Covers Over $\\bbb{f}_5$ and $\\bbb{f}_7$(2013) Özbudak, Ferruh; Temür, Burcu Gülmez; Yayla, OğuzIn this paper we make an exhaustive computer search for finding new curves with many points among fibre products of 2 Kummer covers of the projective line over F5 and F7 . At the end of the search, we have 12 records and 6 new entries for the current Table of Curves with Many Points. In particular, we observe that the fibre product $y^3_1$ = $\\frac {5(x+2)(x +5)} {x}$, $y^3_2$ $\\frac {3x^2(x +5)} {x + 3}$ over F7 has genus 7 with 36 rational points. As this coincides with the Ihara bound, we conclude that the maximum number N7 (7) of F7 -rational points among all curves of genus 7 is 36. Our exhaustive search has been possible because of the methods given in the recent work by Özbudak and Temür (2012) for determining the number of rational points of such curves.Article Citation - WoS: 1Citation - Scopus: 2Role of Surveillance Screening in Detecting Tumor Recurrence After Treatment of Childhood Cancers(Aves, 2021) Kısa, Pelin Teke; Emir, SunaObjective: As the survival rates in children with cancer reach up to 80%, this improvement in survival increases the number of patients under follow-up. After cancer treatment is completed, patients are taken to follow-up surveillance to ensure the early detection of recurrence and the late effects of treatments. The frequency and necessity of surveillance screening tests are controversial. This study aimed to assess the efficacy of surveillance screening in the detection of recurrence. Material and methods: The files of 533 children who were diagnosed as having cancer at our pediatric oncology clinic between 2004 and 2013 were retrospectively evaluated. We looked at outcomes after recurrence, the timing and pattern of recurrence, the presence of symptoms during recurrence, physical examination findings, tumor marker levels, laboratory findings, and radiologic tests. Results: Of the 63 patients with recurrence, 23 were symptomatic and 40 were asymptomatic at the time of the recurrence. Tumor location and time of the recurrence did not affect the post recurrence survival. The median post-recurrence survival for patients was 13 (range, 1-98) months. The median post-relapse survival was 10 (range, 1-73) months in patients with symp-tomatic recurrence, and 16 (range, 1-98) months in patients with asymptomatic recurrence. It was determined that patients in whom recurrence was identified with surveillance tests had longer post-relapse survival time. The 5-year survival rate of 23 patients with symptomatic recurrence was 12.2%; this rate was 49.5% in asymptomatic patients (p<0.05).Conclusions: It should be considered that surveillance testing offers the benefit of prolonging post recurrence survival.Article A Note on the Generalized Matsumoto Relation(2017) Dalyan, Elif; Medetoğulları, Elif; Pamuk, MehmetcikWe give an elementary proof of a relation, first discovered in its full generality by Korkmaz, in the mapping class group of a closed orientable surface. Our proof uses only the well-known relations between Dehn twists.Article Citation - WoS: 1Citation - Scopus: 1On Some Permutation Trinomials in Characteristic Three(Hacettepe Univ, Fac Sci, 2025) Temür, Burcu Gülmez; Özkaya, BuketIn this paper, we determine the permutation properties of the polynomial x3 +xq+2 −x4q−1 over the finite field Fq2 in characteristic three. Moreover, we consider the trinomials of the form x4q−1 + x2q+1 ± x3. In particular, we first show that x3 + xq+2 − x4q−1 permutes Fq2 with q = 3m if and only if m is odd. This enables us to show that the sufficient condition in [34, Theorem 4] is also necessary. Next, we prove that x4q−1 + x2q+1 − x3 permutes Fq2 with q = 3m if and only if m ̸≡ 0 (mod 4). Consequently, we prove that the sufficient condition in [20, Theorem 3.2] is also necessary. Finally, we investigate the trinomial x4q−1 + x2q+1 + x3 and show that it is never a permutation polynomial of Fq2 in any characteristic. All the polynomials considered in this work are not quasi-multiplicative equivalent to any known class of permutation trinomials.Article Fedja’s Proof of Deepti’s Inequality(Tubitak Scientific & Technological Research Council Turkey, 2018) Ostrovska, Sofiya; Turan, MehmetThe paper aims to present, in a systematic way, an elegant proof of Deepti’s inequality. Both the inequalityand various ideas concerning the issue were discussed on the Mathoverflow website by a number of users, but none haveappeared in the literature thus far. In this work, suggestions pertaining to users ‘Deepti’ and ‘fedja’ are traced, whencethe title. The results or the paper are new, and the proof is divided into a series of statements, many of which are ofinterest in themselves.Article Citation - WoS: 1Citation - Scopus: 1A Short Note on Some Arithmetical Properties of the Integer Part of Ap(Tubitak Scientific & Technological Research Council Turkey, 2019) Akbal, YıldırımLet $a>0$ be an irrational number. We study some of the arithmetical properties of ${\\{\\lfloor ap\\rfloor\\}}_{p=2}^\\infty$ where pdenotes a prime number and $\\lfloor x\\rfloor$ denotes the largest integer not exceeding x.Article Citation - WoS: 4Citation - Scopus: 5Construction of a Complex Jacobi Matrix From Two-Spectra(Hacettepe Univ, Fac Sci, 2011) Guseinov, Gusein Sh; MathematicsIn this paper we study the inverse spectral problem for two-spectra of finite order complex Jacobi matrices (tri-diagonal matrices). The problem is to reconstruct the matrix using two sets of eigenvalues, one for the original Jacobi matrix and one for the matrix obtained by deleting the first column and the first row of the Jacobi matrix. An explicit procedure of reconstruction of the matrix from the two-spectra is given.Article Citation - WoS: 16Citation - Scopus: 20Common Fixed Point Theorems in Cone Banach Spaces(Hacettepe Univ, Fac Sci, 2011) Abdeljawad, Thabet; Karapinar, Erdal; Tas, Kenan; MathematicsRecently, E. Karapinar (Fixed Point Theorems in Cone Banach Spaces, Fixed Point Theory Applications, Article ID 609281, 9 pages, 2009) presented some fixed point theorems for self-mappings satisfying certain contraction principles on a cone Banach space. Here we will give some generalizations of this theorem.
- «
- 1 (current)
- 2
- 3
- »