Advertising a new product in a segmented market

We bring some market segmentation concepts into the statement of the “new product introduction” problem with Nerlove-Arrow’s linear goodwill dynamics. In fact, only a few papers on dynamic quantitative advertising models deal with market segmentation, although this is a fundamental topic of marketing theory and practice. In this way we obtain some new deterministic optimal control problems solutions and show how such marketing concepts as “targeting” and “segmenting” may find a mathematical representation. We consider two kinds of situations. In the first one, we assume that the advertising process can reach selectively each target group. In the second one, we assume that one advertising channel is available and that it has an effectiveness segment-spectrum, which is distributed over a non-trivial set of segments. We obtain the explicit optimal solutions of the relevant problems.     

Problem solving in Chinese mathematics education: research and practice

This paper is an attempt to paint a picture of problem solving in Chinese mathematics education, where problem solving has been viewed both as an instructional goal and as an instructional approach. In discussing problem-solving research from four perspectives, it is found that the research in China has been much more content and experience-based than cognitive and empirical-based. We also describe several problem-solving activities in the Chinese classroom, including “one problem multiple solutions,” “multiple problems one solution,” and “one problem multiple changes.” Unfortunately, there are no empirical investigations that document the actual effectiveness and reasons for the effectiveness of those problem-solving activities. Nevertheless, these problem-solving activities should be useful references for helping students make sense of mathematics.     

Mathematikdidaktik: Die Erforschung theoretischen Wissens in sozialen Kontexten des Lernens und Lehrens

The problem of “defining” mathematics education as a proper scientific discipline has been discussed controversely for more than 20 years now. The paper tries to clarify some important aspects especially for answering the question of what makes mathematics education a specific scientific discipline and a field of research. With this aim in mind the following two dimensions are investigated: On the one hand, one has to be aware that mathematics is not “per se” the object of research in mathematics education, but that mathematical knowledge always has to be regarded as being “situated” within a social context. This means that mathematical knowledge only gains its specific epistemological meaning within a social context and that the development and understanding of mathematical knowledge is strongly influenced by the social context. On the other hand the specificity of the theory-practice-problem poses an essential demand on the scientific work in mathematics education.     

T. S. Kuhn's theories and mathematics: A discussion paper on the “new historiography” of mathematics

A discussion of the applicability of the concepts of T. S. Kuhn's theory of scientific revolutions, stimulated by the statement by M. J. Crowe of ten “laws” concerning change in the history of mathematics. The concepts “revolution” and “crisis” are rejected, while the concepts centering around the sociology of the scientific community are accepted for systematic use in historiography of mathematics. This is supplemented by the consideration of extra-mathematical influences. Finally the “laws” of Crowe are shown to be explainable with those concepts.     

On the minimal representation of homogeneous games

It is known that the lattice-minimal representation (by natural numbers) of a weighted majority game may be not unique and may lack of equal treatment (Isbell 1959). The same is true for the total-weight minimal representation. Both concepts coincide on the class of homogeneous games. The main theorem of this article is that for homogeneous games there is a unique minimal representation. This result is given by means of a construction that depends on the natural order on the set of player types. This order coincides with one induced by the “desirability relation”. In order to compute the minimal representation inductively, while proceeding from smaller players to the greater one, we are led to distinguish two different kinds of players: some players are “replacable” by smaller ones, some not.     

Visage—Visualization of algorithms in discrete mathematics

Which route should the garbage collectors' truck take? Just a simple question, but also the starting point of an exciting mathematics class. The only “hardware” you need is a city map, given on a sheet of paper or on the computer screen. Then lively discussions will take place in the classroom on how to find an optimal routing for the truck. The aim of this activity is to develop an algorithm that constructs Eulerian tours in graphs and to learn about graphs and their properties. This teaching sequence, and those stemming from discrete mathematics, in particular combinatorial optimization, are ideal for training problem solving skills and modeling—general competencies that, influenced by the German National Standards, are finding their way into curricula. In this article, we investigate how computers can help in providing individual teaching tools for students. Within the Visage project we focus on electronic activities that can enhance explorations with graphs and guide studients even if the teacher is not available—without taking away freedom and creativity. The software package is embedded into a standard DGS, and it offers many pre-built and teacher-customizable tools in the area of graph algorithms. Until now, there are no complete didactical concepts for teaching graph algorithms, in particular using new media. We see a huge potential in our methods, and the topic is highly requested on part of the teachers, as it introduces a modern and highly relevant part of mathematics into the curriculum.     

How real are virtual realities,how virtual is reality?—Constructive re-interpretation of physical undecidability

Throughout the ups and downs of scientific world conception there has been a persistent vision of a world which is understandable by human reasoning. In a contemporary, recursion theoretic, comprehension, the term “reasoning” is interpretable as “constructive” or, more specifically, “mechanically computable.” An expression of this statement is the assumption that our universe is generated by the action of some deterministic computing agent; or, stated pointedly, that we are living in a computer-generated universe. Physics then reduces to the investigation of the intrinsic, “inner view” of a particular virtual reality which happens to be our universe. In this interpretation, formal logic, mathematics and the computer sciences are just the physical sciences of more general “virtual” realities, irrespective of whether they are “really” realized or not. We shall study several aspects of this conception, among them the conjecture that randomness in physics can be constructively reinterpreted to correspond to uncomputability and undecidability in mathematics. We shall also attack the nonconstructive feature of classical physics by showing its inconsistency. Another concern is the modeling of interfaces, i.e., the means and methods of communication between two universes. On a speculative level, this may give some clue on such notorious questions such as the occurrence of “miracles” or on the “mind-body problem.”     

Mathematical modelling in university education. An experiment at the University of Oldenburg

This paper suggests that mathematics teacher educators should listen carefully to what their students are saying. More specifically, it demonstrates how from one pre-teacher's non-traditional geometric representation of a unit fraction, a variety of learning environments that lead to the enrichment of mathematics for teaching can be developed. The paper shows how new knowledge may be generated through an attempt to validate an intuitive idea; in other words, how the quest for rigour may serve as a catalyst for the growth of mathematical concepts in the context of K-16 mathematics.     

Mathematical problem solving in didactic institutions as a complex system: The case of elementary calculus

The question of problem-solving activities in didactic institutions is critical in mathematics education for two important reasons. It is a main factor of learning according to Piaget, and it is a means for students to try to align their behaviors to expected institutional references. Mathematical reasoning during problem solving in didactic institutions is studied in the present work as a complex system of interfering constraints. Results tend to show that this system may be understood as being ruled by ternary interactions between three poles: the student, the teacher, and the knowledge itself. Simultaneously, theoretical and pragmatic considerations are focused on problem solving in mathematics: the specific epistemological difficulties of each domain of knowledge to be studied, the computational asymmetry between mathematical concepts and procedures, and the influence of implicit teacher expectations through students' decoding of local “didactic contracts.”     

A model of concept formation

At first we model the way an intelligence “I” constructs statements from phrases, and then how “I” interlocks these statements to form a string of statements to attain a concept. These strings of statements are called progressions. That is, starting with an initial stimulating relation between two phrases, we study how “I” forms the first statement of the progression and continues from this first statement to form the remaining statements in these progressions to construct a concept. We assume that “I” retains the progressions that it has constructed. Then we show how these retained progressions provide “I” with a platform to incrementally constructs more and more sophisticated conceptual structures. The reason for the construction of these conceptual structures is to achieve additional concepts. Choice plays a very important role in the progression and concept formation. We show that as “I” forms new concepts, it enriches its conceptual structure and makes further concepts attainable. This incremental attainment of concepts is a way in which we humans learn, and this paper studies the attainability of concepts from previously attained concepts. We also study the ability of “I” to apply its progressions and also the ability of “I” to electively manipulate its conceptual structure to achieve new concepts. Application and elective manipulation requires of “I” ingenuity and insight. We also show that as “I” attains new concepts, the conceptual structures change and circumstances arise where unanticipated conceptual discoveries are attainable. As the conceptual structure of “I” is developed, the logical and structural relationships between concepts embedded in this structure also develop. These relationships help “I” understand concepts in the context of other concepts and help “I₁” communicate to another “I₂” information and concept structures. The conceptual structures formed by “I” give rise to a directed web of statement paths which is called a convolution web. The convolution web provides “I” with the paths along which it can reason and obtain new concepts and alternative ways to attain a given concept.This paper is an extension of the ideas introduced in [1]. It is written to be self-contained and the required background is supplied as needed.     

Perspectives sur les recherches en didactique des mathématiques

The paper is a review of chosen approaches to research in mathematics education in several countries: Germany, France, United States, Russia, Poland, Canada. The review is done in the literary form of a satire, in which a character is taken on a voyage to a variety of “islands” respresenting different research interests and methodologies in mathematics education. The story is a parody of Homer’sOdyssee, and the main character is called Odysseus. Odysseus’ role is played by the famous arithmetic problem about a team of an unknown number of scythers who are given the task of scything two meadows one of which is double the size of the other. As the problem travels from one “island” to another, mathematics educators do different things to and with the problem and it is solved is a variety of ways. The main text of the paper reads as a story and there are no explicit references and names of authors, whose work is only alluded to. However, the solution to all allusions, i.e. explicit references, can be found in the footnotes.     

A Tractable and Expressive Class of Marginal Contribution Nets and Its Applications

Coalitional games raise a number of important questions from the point of view of computer science, key among them being how to represent such games compactly, and how to efficiently compute solution concepts assuming such representations. Marginal contribution nets (MC‐nets), introduced by Ieong and Shoham, are one of the simplest and most influential representation schemes for coalitional games. MC‐nets are a rulebased formalism, in which rules take the form pattern → value, where “pattern ” is a Boolean condition over agents, and “value ” is a numeric value. Ieong and Shoham showed that, for a class of what we will call “basic” MC‐nets, where patterns are constrained to be a conjunction of literals, marginal contribution nets permit the easy computation of solution concepts such as the Shapley value. However, there are very natural classes of coalitional games that require an exponential number of such basic MC‐net rules. We present read‐once MC‐nets, a new class of MC‐nets that is provably more compact than basic MC‐nets, while retaining the attractive computational properties of basic MC‐nets. We show how the techniques we develop for read‐once MC‐nets can be applied to other domains, in particular, computing solution concepts in network flow games on series‐parallel networks (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Is the definition of mathematics as used in the PISA assessment Framework applicable to the HarmoS Project?

The project known as the “Harmonisation of the Obligatory School”, or in its shortened form as “HarmoS”, has a high priority for Switzerland's educational policy in the coming years. Its purpose is to determine levels of competency, valid throughout Switzerland, for specific areas of study and including the subject of mathematics. The general theoretical basis of the overall HarmoS Project is constituted by the expertise written under the direction of Eckhard Klieme and entitled “Zur Entwicklung nationaler Bildungsstandards” (Klieme 2003) [i.e. “On the Development of National Education Standards”]. The proposal announcing the HarmoS partial project devoted to Mathematics includes references to the results and subsequent analysis of PISA 2003. It thus seems appropriate for us to begin our work on HarmoS with a critical consideration of the definition of mathematics and mathematical literacy as they are used in the PISA Study. In a first part, we want to describe the core ideas of HarmoS. In a second part, we will address the meaning of general educational goals for the development of competency models and education standards to the extent that it is necessary to properly locate our problem. In a third part we will analyse the concept of mathematics which is at the basis of the PISA Study (OECD 2004) and more precisely defined in the publication “Assessment Framework” (OECD 2003) In the fourth and last part, we will try to provide a differentiated answer to the question posed in the title of this paper.     

From evidence-based policy making to policy analytics

This paper aims at addressing the problem of what characterises decision-aiding for public policy making problem situations. Under such a perspective it analyses concepts like “public policy”, “deliberation”, “legitimation”, “accountability” and shows the need to expand the concept of rationality which is expected to support the acceptability of a public policy. We then analyse the more recent attempt to construct a rational support for policy making, the “evidence-based policy making” approach. Despite the innovation introduced with this approach, we show that it basically fails to address the deep reasons why supporting the design, implementation and assessment of public policies is such a hard problem. We finally show that we need to move one step ahead, specialising decision-aiding to meet the policy cycle requirements: a need for policy analytics.     

The mathematics of war

During the Desert Storm, the Gulf war, it was possible to read in the newspapers words such as: “Inmathematical terms, was is becoming more and more electronically controlled and, as a result, it is moving away from the battlefield. Then, when war comes down to earth, it becomes bloody, it loses its mathematical asceticism” Reading the newspapers in those days, one had the impression that modern warfare is based on mathematics, as if it were not men but computers that decided where to carry out “surgical operations”. By contrast, the volume published a few years before the Gulf war conceived as a didactic unit to be used in schools with a guide for the teacher with the titleLa matematica della guerra (The Mathematics of War) published by Gruppo Abele in Turin begins with the words “Mathematics, like any other discipline, lends itself to building several paths towards education for peace”. The volume, written by a group of teachers belonging to an anti-violence organisation forming part of the “education for peace” project, highlights the power or ambiguitiy of mathematical models used to simulate war or conflict situations and demonstrates that in some cases the use of mathematics leads to a better understanding of the situation, but in other cases, the mathematical model itself can lead to conclusions which are either wrong or morally unacceptable.     

Problem solving in the United States, 1970–2008: research and theory, practice and politics

Problem solving was a major focus of mathematics education research in the US from the mid-1970s though the late 1980s. By the mid-1990s research under the banner of “problem solving” was seen less frequently as the field’s attention turned to other areas. However, research in those areas did incorporate some ideas from the problem solving research, and that work continues to evolve in important ways. In curricular terms, the problem solving research of the 1970s and 1980s (see, e.g., Lester in J Res Math Educ, 25(6), 660–675, 1994, and Schoenfeld in Handbook for research on mathematics teaching and learning, MacMillan, New York, pp 334–370, 1992, for reviews) gave birth to the “reform” or “standards-based” curriculum movement. New curricula embodying ideas from the research were created in the 1990s and began to enter the marketplace. These curricula were controversial. Despite evidence that they tend to produce positive results, they may well fall victim to the “math wars” as the “back to basics” movement in the US is revitalized.     

Hong Kong teachers’ views of effective mathematics teaching and learning

Twelve experienced mathematics teachers in Hong Kong were invited to face-to-face semi-structured interviews to express their views about mathematics, about mathematics learning and about the teacher and teaching. Mathematics was generally regarded as a subject that is practical, logical, useful and involves thinking. In view of the abstract nature of the subject, the teachers took abstract thinking as the goal of mathematics learning. They reflected that it is not just a matter of “how” and “when”, but one should build a path so that students can proceed from the concrete to the abstract. Their conceptions of mathematics understanding were tapped. Furthermore, the roles of memorisation, practices and concrete experiences were discussed, in relation with understanding. Teaching for understanding is unanimously supported and along this line, the characteristics of an effective mathematics lesson and of an effective mathematics teacher were discussed. Though many of the participants realize that there is no fixed rule for good practices, some of the indicators were put forth. To arrive at an effective mathematics lesson, good preparation, basic teaching skills and good relationship with the students are prerequisite.     

The Mathematics Writer's Checklist: The Development of a Preliminary Assessment Tool for Writing in Mathematics

The use of writing as a pedagogical tool to help students learn mathematics is receiving increased attention at the college level ( Meier & Rishel, 1998 ), and the Principles and Standards for School Mathematics (NCTM, 2000) built a strong case for including writing in school mathematics, suggesting that writing enhances students' mathematical thinking. Yet, classroom experience indicates that not all students are able to write well about mathematics. This study examines the writing of a two groups of students in a college‐level calculus class in order to identify criteria that discriminate “;successful” vs. “;unsuccessful” writers in mathematics. Results indicate that “;successful” writers are more likely than “;unsuccessful” writers to use appropriate mathematical language, build a context for their writing, use a variety of examples for elaboration, include multiple modes of representation (algebraic, graphical, numeric) for their ideas, use appropriate mathematical notation, and address all topics specified in the assignment. These six criteria result in The Mathematics Writer's Checklist, and methods for its use as an instructional and assessment tool in the mathematics classroom are discussed.     

Basic skills versus conceptual understanding in mathematics education: The case of fraction division

The distinction between conceptual understanding and basic skills is as old as mathematics education research itself. It still remains a central issue for many disputes. In this paper, building upon professor Hung-Hsi Wu's rejection of the distinction, I explore three possible accounts of it: (a) conceptual understanding first, (b) explaining the distinction away and emphasizing “procedural-understanding” instead, and finally (c) treating understanding and procedural skill as two separate, irreducible, complementary components. In contrast to Wu who favors the second account, I argue that as far as mathematics teaching is concerned the third view is the preferable one