Thesis (D.A.)--Illinois State University, 1983. / Title from title page screen, viewed May 11, 2005. Dissertation Committee: Albert D. Otto (chair), John A. Dossey, Kenneth A. Retzer, Linnea L. Sennott, Seth F. Carmody. Includes bibliographical references (leaves 27-28) and abstract. Also available in print.

O objetivo deste trabalho é fazer um estudo amplo e sequencial sobre combinatória. Iniciase com os fundamentos da combinatória enumerativa, tais como permutações, combinações simples, combinações completas e os lemas de Kaplanski. Num segundo momento é apresentado uma abordagem aos problemas de contagem utilizando a teoria de conjuntos; são abordados o princípio da inclusão-exclusão, permutações caóticas e a contagem de funções. No terceiro momento é feito um aprofundamento do conceito de permutação sob a ótica da álgebra abstrata. É explorado o conceito de grupo de permutações e resultados importantes relacionados. Na sequência propõe-se uma relação de ordem completa e estrita para o grupo de permutações. Por fim, investiga-se dois problemas interessantes da combinatória: a determinação do número de caminhos numa malha quadriculada e a contagem de permutações que desconhecem padrões de comprimento três. / The objective of this work is to make a broad and sequential study on combinatorics. It begins with the foundations of enumerative combinatorics, such as permutations, simple combinations, complete combinations, and Kaplanskis lemmas. In a second moment an approach is presented to the counting problems using set theory; the principle of inclusion-exclusion, chaotic permutations and the counting of functions are addressed. In the third moment a deepening of the concept of permutation is made from the perspective of abstract algebra. The concept of group of permutations and related important results is explored. A strict total order relation for the permutation group is proposed. Finally, we investigate two interesting combinatorial problems: the determination of the number of paths in a grid and the number of permutations that avoids patterns of length three.

O objetivo deste trabalho é fazer um estudo amplo e sequencial sobre combinatória. Iniciase com os fundamentos da combinatória enumerativa, tais como permutações, combinações simples, combinações completas e os lemas de Kaplanski. Num segundo momento é apresentado uma abordagem aos problemas de contagem utilizando a teoria de conjuntos; são abordados o princípio da inclusão-exclusão, permutações caóticas e a contagem de funções. No terceiro momento é feito um aprofundamento do conceito de permutação sob a ótica da álgebra abstrata. É explorado o conceito de grupo de permutações e resultados importantes relacionados. Na sequência propõe-se uma relação de ordem completa e estrita para o grupo de permutações. Por fim, investiga-se dois problemas interessantes da combinatória: a determinação do número de caminhos numa malha quadriculada e a contagem de permutações que desconhecem padrões de comprimento três. / The objective of this work is to make a broad and sequential study on combinatorics. It begins with the foundations of enumerative combinatorics, such as permutations, simple combinations, complete combinations, and Kaplanskis lemmas. In a second moment an approach is presented to the counting problems using set theory; the principle of inclusion-exclusion, chaotic permutations and the counting of functions are addressed. In the third moment a deepening of the concept of permutation is made from the perspective of abstract algebra. The concept of group of permutations and related important results is explored. A strict total order relation for the permutation group is proposed. Finally, we investigate two interesting combinatorial problems: the determination of the number of paths in a grid and the number of permutations that avoids patterns of length three.

No description available.

This paper is an investigation of several basic properties of noetherian rings. Chapter I gives a brief introduction, statements of definitions, and statements of theorems without proof. Some of the main results in the study of noetherian rings are proved in Chapter II. These results include proofs of the equivalence of the maximal condition, the ascending chain condition, and that every ideal is finitely generated. Some other results are that if a ring R is noetherian, then R[x] is noetherian, and that if every prime ideal of a ring R is finitely generated, then R is noetherian.

The primary objects of study in this thesis are noncommutative surfaces; that is, noncommutative noetherian domains of GK dimension 2. Frequently these rings will also be singular, in the sense that they have infinite global dimension. Very little is known about singularities of noncommutative rings, particularly those which are not finite over their centre. In this thesis, we are able to give a precise description of the singularities of a few families of examples. In many examples, we lay the foundations of noncommutative singularity theory by giving a precise description of the singularities of the fundamental examples of noncommutative surfaces. We draw comparisons with the fundamental examples of commutative surface singularities, called Kleinian singularities, which arise from the action of a finite subgroup of SL(2; k) acting on a polynomial ring. The main tool we use to study the singularities of noncommutative surfaces is the singularity category, first introduced by Buchweitz in [Buc86]. This takes a (possibly noncommutative) ring R and produces a triangulated category Dsg(R) which provides a measure of "how singular" R is. Roughly speaking, the size of this category reflects how bad the singularity is; in particular, Dsg(R) is trivial if and only if R has finite global dimension. In [CBH98], Crawley-Boevey-Holland introduced a family of noncommutative rings which can be thought of as deformations of the coordinate ring of a Kleinian singularity. We give a precise description of the singularity categories of these deformations, and show that their singularities can be thought of as unions of (commutative) Kleinian singularities. In particular, our results show that deforming a singularity in this setting makes it no worse. Another family of noncommutative surfaces were introduced by Rogalski-Sierra-Stafford in [RSS15b]. The authors showed that these rings share a number of ring-theoretic properties with deformations of type A Kleinian singularities. We apply our techniques to show that the "least singular" example has an A1 singularity, and conjecture that other examples exhibit similar behaviour. In [CKWZ16a], Chan-Kirkman-Walton-Zhang gave a definition for a quantum version of Kleinian singularities. These require the data of a two-dimensional AS regular algebra A and a finite group G acting on A with trivial homological determinant. We extend a number of results in [CBH98] to the setting of quantum Kleinian singularities. More precisely, we show that one can construct deformations of the skew group rings A#G and the invariant rings AG, and then determine some of their ring-theoretic properties. These results allow us to give a precise description of the singularity categories of quantum Kleinian singularities, which often have very different behaviour to their non-quantum analogues.

No description available.

I examined the development of three Prospective Secondary Mathematics Teachers' (PSMTs) understandings of connections between concepts in Abstract Algebra and high school Algebra, as well as their use of this understanding while engaging in the teaching practice of noticing students' mathematical thinking. I drew on the theory, Knowledge of Nonlocal Mathematics for Teaching, which suggests that teachers' knowledge of advanced mathematics can become useful for teaching when it first helps reshape their understanding of the content they teach. I examined this reshaping process by investigating how PSMTs extended, deepened, unified, and strengthened their understanding of inverses, identities, and binary operations over time. I investigated how the PSMTs' engagement in a Mathematics for Secondary Teachers course, which covered connections between inverse functions and equation solving and the abstract algebraic structures of groups and rings, supported the reshaping of their understandings. I then explored how the PSMTs used their mathematical knowledge as they engaged in the teaching practice of noticing hypothetical students' mathematical thinking. I investigated the extent to which the PSMTs' noticing skills of attending, interpreting, and deciding how to respond to student thinking developed as their mathematical understandings were reshaped. There were key similarities in how the PSMTs reshaped their knowledge of inverse, identity, and binary operation. The PSMTs all unified the additive identity, multiplicative identity, and identity function as instantiations of the same overarching identity concept. They each deepened their understanding of inverse functions. They all unified additive, multiplicative, and function inverses under the overarching inverse concept. They also strengthened connections between inverse functions, the identity function, and function composition. They all extended the contexts in which their understandings of inverses were situated to include trigonometric functions. These changes were observed across all the cases, but one change in understanding was not observed in each case: one PSMT deepened his understanding of the identity function, whereas the other two had not yet conceptualized the identity function as a function in its own right; rather, they perceived it as x, the output of the composition of inverse functions. The PSMTs had opportunities to develop these understandings in their Mathematics for Secondary Teachers course, in which the instructor led the students to reason about the inverse and identity group axioms and reflect on the structure of additive, multiplicative, and compositional inverses and identities. The course also covered the use of inverses, identities, and binary operations used while performing cancellation in the context of equation solving. The PSMTs' noticing skills improved as their mathematical knowledge was reshaped. The PSMTs' reshaped understandings supported them paying more attention to the properties and strategies evident in a hypothetical student's work and know which details were relevant to attend to. The PSMTs' reshaped understandings helped them more accurately interpret a hypothetical student's understanding of the properties, structures, and operations used in equation solving and problems about inverse functions. Their reshaped understandings also helped them give more accurate and appropriate suggestions for responding to a hypothetical student in ways that would build on and improve the student's understanding. / Doctor of Philosophy / Once future mathematics teachers learn about how advanced mathematics content is related to high school algebra content, they can better understand the algebra content they may teach. The future teachers in this study took a Mathematics for Secondary Teachers course during their senior year of college. This course gave them opportunities to make connections between advanced mathematics and high school mathematics. After this course, they better understood the mathematical properties that people use while equation solving, and they improved their teaching practice of making sense of high school students' mathematical thinking about inverses and equation solving. Overall, making connections between the advanced mathematics content they learned during college and the algebra content related to inverses and equation solving that they teach in high school helped them improve their teaching practice.

In this research, I set out to elucidate the relationships that might exist between students' conceptual understanding upon which they draw in their proof activity. I explore these relationships using data from individual interviews with three students from a junior-level Modern Algebra course. Each phase of analysis was iterative, consisting of iterative coding drawing on grounded theory methodology (Charmaz, 2000, 2006; Glaser and Strauss, 1967). In the first phase, I analyzed the participants' interview responses to model their conceptual understanding by drawing on the form/function framework (Saxe, et al., 1998). I then analyzed the participants proof activity using Aberdein's (2006a, 2006b) extension of Toulmin's (1969) model of argumentation. Finally, I analyzed across participants' proofs to analyze emerging patterns of relationships between the models of participants' understanding of identity and inverse and the participants' proof activity. These analyses contributed to the development of three emerging constructs: form shifts in service of sense-making, re-claiming, and lemma generation. These three constructs provide insight into how conceptual understanding relates to proof activity. / Ph. D.

The Teaching Abstract Algebra for Understanding (TAAFU) project was centered on an innovative abstract algebra curriculum and was designed to accomplish three main objectives: to produce a set of multi-media support materials for instructors, to understand the challenges faced by mathematicians as they implemented this curriculum, and to study how this curriculum supports student learning of abstract algebra. Throughout the course of the project I took the lead investigating the teaching and learning in classrooms using the TAAFU curriculum. My dissertation is composed of three components of this research. First, I will report on a study that aimed to describe the experiences of mathematicians implementing the curriculum from their perspective. Second. I will describe a study that explores the mathematical work done by teachers as they respond to the mathematical activity of their students. Finally, I will discuss a theoretical paper in which I synthesize aspects of the instructional theory underlying the TAAFU curriculum in order to develop an analytic framework for analyzing student learning. This dissertation will serve as a foundation for my future research focused on the relationship between teachers' mathematical work and the learning of their students.