Modifying Faug\`ere's F5 Algorithm to ensure termination

The structure of the F5 algorithm to compute Gr\"obner bases makes it very efficient. However, while it is believed to terminate for so-called regular sequences, it is not clear whether it terminates for all inputs. This paper has two major parts. In the first part, we describe in detail the difficulties related to a proof of termination. In the second part, we explore three variants that ensure termination. Two of these have appeared previously only in dissertations, and ensure termination by checking for a Gr\"obner basis using traditional criteria. The third variant, F5+, identifies a degree bound using a distinction between "necessary" and "redundant" critical pairs that follows from the analysis in the first part. Experimental evidence suggests this third approach is the most efficient of the three.Comment: 19 pages, 1 tabl

On the Origin of the Family

This paper presents an overlapping generations model to explain why humans live in families rather than in other pair groupings. Since most non-human species are not familial, something special must be behind the family. It is shown that the two necessary features that explain the origin of the family are given by uncertain paternity and overlapping cohorts of dependent children. With such two features built into our model, and under the assumption that individuals care only for the propagation of their own genes, our analysis indicates that fidelity families dominate promiscuous pair bonding, in the sense that they can achieve greater survivorship and enhanced genetic fitness. The explanation lies in the free riding behavior that characterizes the interactions between competing fathers in the same promiscuous pair grouping. Kin ties could also be related to the emergence of the family. When we consider a kinship system in which an adult male transfers resources not just to his offspring but also to his younger siblings, we find that kin ties never emerge as an equilibrium outcome in a promiscuous environment. In a fidelity family environment, instead, kinship can occur in equilibrium and, when it does, it is efficiency enhancing in terms of greater survivorship and fitness. The model can also be used to shed light on the issue as to why virtually all major world religions are centered around the importance of the family.fatherhood uncertainty, free riding, kinship systems, religion, overlapping generations, divorce and blended families

GeSn Thin Film Epitaxy and Quantum Wells for Optoelectronic Devices

Group IV photonics is an effort to generate viable infrared optoelectronic devices using group IV materials. Si-based optoelectronics have received monumental research since Si is the heart of the electronics industry propelling our data driven world. Silicon however, is an indirect material whose optical characteristics are poor compared to other III-IV semiconductors that make up the optoelectronics industry. There have been major efforts to integrate III-V materials onto Si substrates. Great progress on the integration of these III-V materials has occurred but incompatibility with CMOS processing has presented great difficulty in this process becoming a viable and cost-effective solution. Germanium has also been studied and shown to produce direct bandgaps through tensile strain but have limited wavelength coverage. Research into group IV photonics has produced Sn-based materials which have shown promise in achieving efficient infrared optoelectronic devices on Si substrates. The GeSn material has already shown to be direct bandgap with a number of optically active devices already demonstrated. The work presented in this dissertation was focused on the development of ultra-high vacuum chemical vapor deposition of epitaxially grown high optical quality GeSn material. Low temperature Ge and dilute GeSn films were grown directly on Si. Development of Ge buffers on Si for high optical quality GeSn was also accomplished. Growth of GeSn on Ge buffers started under a Sn over-pressure condition. Reduction of the SnCl4 molar flow fraction led to high quality optical material. Material and optical characterization were carried out using x-ray diffraction, transmission electron microscopy, photoluminescence and other methods to determine the Sn composition and optical and material qualites. Additionally, GeSn and SiGeSn barriered GeSn quantum wells grown using a commercial reduced pressure chemical vapor deposition chamber were characterized. The structures were grown on Ge and GeSn buffered Si with up to 9.5% Sn in the buffer. The bandstructure was simulated and compared against optical characterization to verify the simulation results and estimate the carrier confinement in the structures. Increasing the Sn in the GeSn buffer puts more Sn in the well, and wide wells provide enhanced confinement, suggesting a route toward efficient mid-infrared emitters

On the Origin of the Family

This paper presents an overlapping generations model to explain why humans live in families rather than in other pair groupings. Since most non-human species are not familial, something special must be behind the family. It is shown that the two necessary features that explain the origin of the family are given by uncertain paternity and overlapping cohorts of dependent children. With such two features built into our model, and under the assumption that individuals care only for the propagation of their own genes, our analysis indicates that fidelity families dominate promiscuous pair bonding, in the sense that they can achieve greater survivorship and enhanced genetic fitness. The explanation lies in the free riding behavior that characterizes the interactions between competing fathers in the same promiscuous pair grouping. Kin ties could also be related to the emergence of the family. When we consider a kinship system in which an adult male transfers resources not just to his offspring but also to his younger siblings, we find that kin ties never emerge as an equilibrium outcome in a promiscuous environment. In a fidelity family environment, instead, kinship can occur in equilibrium and, when it does, it is efficiency enhancing in terms of greater survivorship and fitness. The model can also be used to shed light on the issue as to why virtually all major world religions are centered around the importance of the family

On the origin of the family

We present a game theoretic model to explain why people form life long monogamous families. Three components are essential in our framework, paternal investment, fatherhood uncertainty, and, perhaps the most distinctive feature of all, the overlap of children of different ages. When all three conditions are present, monogamy is the most efficient form of sexual organization in the sense that it yields greater survivorship than serial monogamy, group marriage, and polygyny. Monogamy is also the only configuration that fosters altruistic ties among siblings. Finally, our result sheds light to the understanding of why most religions center around the monogamous fidelity family

Роль информационных технологий в становлении образовательного пространства дошкольных учреждений

The paper concentrates on the role of informational technologies in the teaching process in pre-school institutions, describes effective directions of the development of the technologies, and examines the problems which we need in order to implement these technologies in educating childre

On the Size of Hadrons

The form factor and the mean-square radius of the pion are calculated analytically from a parametrized form of a $q\bar q$ wave function. The numerical wave function was obtained previously by solving numerically an eigenvalue equation for the pion in a particular model. The analytical formulas are of more general interest than just be valid for the pion and can be generalized to the case with unequal quark masses. Two different parametrizations are investigated. Because of the highly relativistic problem, noticable deviations from a non-relativistic formula are obtained.Comment: 14 pages, minor typos corrected, several points clarified, results unchange

The EAR Motif in the \u3ci\u3eArabidopsis\u3c/i\u3e MADS Transcription Factor AGAMOUS-Like 15 Is Not Necessary to Promote Somatic Embryogenesis

AGAMOUS-like 15 (AGL15) is a member of the MADS domain family of transcription factors (TFs) that can directly induce and repress target gene expression, and for which promotion of somatic embryogenesis (SE) is positively correlated with accumulation. An ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motif of form LxLxL within the carboxyl-terminal domain of AGL15 was shown to be involved in repression of gene expression. Here, we examine whether AGL15′s ability to repress gene expression is needed to promote SE. While a form of AGL15 where the LxLxL is changed to AxAxA can still promote SE, another form with a strong transcriptional activator at the carboxy-terminal end, does not promote SE and, in fact, is detrimental to SE development. Select target genes were examined for response to the different forms of AGL15