Fekete┐SzegoProblemforStronglyBazilevicFunctions

Ｆｅｋｅｔｅ┐ＳｚｅｇｏＰｒｏｂｌｅｍｆｏｒＳｔｒｏｎｇｌｙＢａｚｉｌｅｖｉｃＦｕｎｃｔｉｏｎｓＧａｏＣｈｕｎｙｉ（高纯一）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＣｈａｎｇｓｈａＣｏｍｍｕｎｉｃａｔｉｏｎｓＩｎｓｔｉｔｕｔｅ，Ｃｈａｎｇｓ...     

On Minimal Surfaces in Space Forms Whose Gauss Imageshave Constant Curvature

ＯｎＭｉｎｉｍａｌＳｕｒｆａｃｅｓｉｎＳｐａｃｅＦｏｒｍｓＷｈｏｓｅＧａｕｓｓＩｍａｇｅｓｈａｖｅＣｏｎｓｔａｎｔＣｕｒｖａｔｕｒｅ￥ＭａｋｏｔｏＳＡＫＡＫＩ（ＤｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＦａｃｕｌｔｙｏｆＳｃｉｅｎｃｅ，Ｈｉｒｏｓ...     

The Convergence of Fuzzy Complex Valued Series

ＴｈｅＣｏｎｖｅｒｇｅｎｃｅｏｆＦｕｚｚｙＣｏｍｐｌｅｘＶａｌｕｅｄＳｅｒｉｅｓＴｈｅＣｏｎｖｅｒｇｅｎｃｅｏｆＦｕｚｚｙＣｏｍｐｌｅｘＶａｌｕｅｄＳｅｒｉｅｓＷａｎｇＧｕｉｊｕｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＴｏｎｇｈｕａＴｅａ...     

A NOTE ON INTERPOLATION OF A CERTAIN CLASS OF FUNCTIONS

ＡＮＯＴＥＯＮＩＮＴＥＲＰＯＬＡＴＩＯＮＯＦＡＣＥＲＴＡＩＮＣＬＡＳＳＯＦＦＵＮＣＴＩＯＮＳ￥ＺＨＵＹＡＯＣＨＥＮ（朱尧辰）（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓ，ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｂｅｉｊ...     

Hypersurfaces with Constant Mean Curvature in Space Forms

Ｈｙｐｅｒｓｕｒｆａｃｅｓ　ｗｉｔｈ　Ｃｏｎｓｔａｎｔ　Ｍｅａｎ　Ｃｕｒｖａｔｕｒｅ　ｉｎ　Ｓｐａｃｅ　ＦｏｒｍｓＨｙｐｅｒｓｕｒｆａｃｅｓｗｉｔｈＣｏｎｓｔａｎｔＭｅａｎＣｕｒｖａｔｕｒｅｉｎＳｐａｃｅＦｏｒｍｓ￥ＳｏｎｇＨｏｎｇｚａｏ；ＨｕＺｅｊ...     

Saks空间中（A）型相容映射的叠合点及公共不动点（英）

ＣｏｉｎｃｉｄｅｎｃｅＰｏｉｎｔｓａｎｄＣｏｍｍｏｎＦｉｘｅｄＰｏｉｎｔｓｆｏｒＣｏｍｐａｔｉｂｌｅＭａｐｓｏｆＴｙｐｅ（Ａ）ｏｎＳａｋｓＳｐａｃｅｓＰ．Ｐ．Ｍｕｒｔｈｙ，Ｂ．Ｋ．Ｓｈａｒｔｒｉａ，Ｙ．Ｊ．ＣｈｏＣｏｉｎｃｉｄｅｎｃｅＰｏｉｎｔｓａｎ...     

GOPPA CODES FROMARTIN-SCHREIER FUNCTION FIELDS

ＧＯＰＰＡＣＯＤＥＳＦＲＯＭＡＲＴＩＮ－ＳＣＨＲＥＩＥＲＦＵＮＣＴＩＯＮＦＩＥＬＤＳ￥ＨＡＮＷＥＮＢＡＯ（ＤｅｐａｔｍｅｌｌｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＳｉｃｈｕａｎＵｎｉｖｅｒｓｉｔｙｔＣｈｅｎｇｄｕ６１００６４，Ｓｉｃｈｕａｎ，Ｃｈｉｎａ．）Ａ...     

On the Irredundant Forms of Fuzzy Switching Functions

ＯｎｔｈｅＩｒｒｅｄｕｎｄａｎｔＦｏｒｍｓｏｆＦｕｚｚｙＳｗｉｔｃｈｉｎＦｕｎｃｔｉｏｎｓTXＯｎｔｈｅＩｒｒｅｄｕｎｄａｎｔＦｏｒｍｓｏｆＦｕｚｚｙＳｗｉｔｃｈｉｎｇＦｕｎｃｔｉｏｎｓＰｅｉＤａｏｗｕ（ＹａｎｃｈｅｎｇＴｅａｃｈｅｒｓＣｏｌｅｇｅ，...     

The Spectral Characterizations of Some Minimal Submanifolds of a Sphere

ＴｈｅＳｐｅｃｔｒａｌＣｈａｒａｃｔｅｒｉｚａｔｉｏｎｓｏｆＳｏｍｅＭｉｎｉｍａｌＳｕｂｍａｎｉｆｏｌｄｓｏｆａＳｐｈｅｒｅＺｈｏｕＺｈｅｎｒｏｎｇ（周振荣）（ＢａｓｉｃＣｏｕｒｓｅＤｅｐａｒｔｍｅｎｔ，ＷｕｈａｎＦｏｏｄＩｎｄｕｓｔｒｙＣｏｌｌｅｇ...     

Existence of the Self-Similar Solutions in the Heat Flow of Harmonic Maps

ＥｘｉｓｔｅｎｃｅｏｆｔｈｅＳｅｌｆＳｉｍｉｌａｒＳｏｌｕｔｉｏｎｓｉｎｔｈｅＨｅａｔＦｌｏｗｏｆＨａｒｍｏｎｉｃＭａｐｓＦａｎＨｕｉｊｕｎ（范辉军）（ＩｎｓｔｉｔｕｔｅｏｆＭａｔｈｅｍａｔｉｃｓ，ＰｅｋｉｎｇＵｎｉｖｅｒｓｉｔｙ，１００８７１）Ｃ...     

The Gergonne and Nagel centers of an n-dimensional simplex

In contrast with the analogous situation for a triangle, the cevians that join the vertices of a tetrahedron to the points where the faces touch the insphere (or the exspheres) are not concurrent in general. This observation led the present author and P. Walker in [4] to devise alternative definitions of the Gergonne and Nagel centers of a tetrahedron that do not assume the concurrence of such cevians and that coincide with the ordinary definitions in the case of a triangle. They then proved that the Gergonne center exists and is unique for all tetrahedra and that the Nagel center, though unique, exists only for tetrahedra that satisfy certain conditions. In this article, we extend these definitions to simplices of any dimension. By keeping the requirement that the Gergonne center be interior and relaxing such a condition for the Nagel center, we prove that both centers exist and are unique for all simplices, thus polishing the definitions and generalizing the results of the above-mentioned article.     

Star partitions on graphs

Given an undirected graph, a star partition is a partition of the nodes into subsets with at least two nodes so that the subgraph induced by each subset has a spanning star. Star partitions are related to well-known problems concerning domination in graphs and edge covering. We focus on the Constrained Star Partition Problem (CSP) that asks for finding a star partition of given cardinality. The problem is new and presents interesting peculiarities. We explore the relation between the cardinalities of star partitions and domatic bipartitions, showing that there are star partitions of any cardinality between minimum and maximum values, and that a similar but weaker result holds for domatic bipartitions. We study the computational complexity of different versions of star partition and domatic bipartition problems, proving that most of them, in particular CSP, constrained domatic bipartition and balanced domatic bipartition, are NP-complete. We also show that star partition problems are polynomial on trees and, more generally, on bounded treewidth graphs. We introduce an integer linear programming formulation that defines a polytope containing all the star partitions of a graph, showing that its vertices have only integral components for trees, which implies that linear programming can be used to solve weighted star partition problems on trees.     

On Carr and Lee’s Correlation Immunization Strategy

In their seminal work Robust Replication of Volatility Derivatives, Carr and Lee show how to robustly price and replicate a variety of claims written on the quadratic variation of a risky asset under the assumption that the asset’s volatility process is independent of the Brownian motion that drives the asset’s price. Additionally, they propose a correlation immunization strategy that minimizes the pricing and hedging error that results when the correlation between the risky asset’s price and volatility is non-zero. In this paper, we show that the correlation immunization strategy is the only strategy among the class of strategies discussed in Carr and Lee's paper that results in real-valued hedging portfolios when the correlation between the asset’s price and volatility is non-zero. Additionally, we perform a number of Monte Carlo experiments to test the effectiveness of Carr and Lee’s immunization strategy. Our results indicate that the correlation immunization method is an effective means of reducing pricing and hedging errors that result from a non-zero correlation.     

The role of framing in productive classroom discussions: A case for teacher learning

In this paper, we contrast two mathematical arguments that occurred during an algebra lesson to illustrate the importance of relevant framings in the ensuing arguments. The lesson is taken from a graduate course for elementary teachers who are enrolled in a mathematics specialist program. We use constructs associated with enthnography of argumentation to characterize the framings for warrants and backings that supported the ensuing arguments. Our findings suggest that teachers fully participated in argumentations that were framed by problem situations that were familiar to them, ones that were couched in elementary, fundamental mathematical ideas, and that these types of argumentations were arguably more productive in terms of opportunities for learning.     

Ring graphs and complete intersection toric ideals

We study the family of graphs whose number of primitive cycles equals its cycle rank. It is shown that this family is precisely the family of ring graphs. Then we study the complete intersection property of toric ideals of bipartite graphs and oriented graphs. An interesting application is that complete intersection toric ideals of bipartite graphs correspond to ring graphs and that these ideals are minimally generated by Gröbner bases. We prove that any graph can be oriented such that its toric ideal is a complete intersection with a universal Gröbner basis determined by the cycles. It turns out that bipartite ring graphs are exactly the bipartite graphs that have complete intersection toric ideals for any orientation.     

Attention to meaning by algebra teachers

Non-attendance to meaning by students is a prevalent phenomenon in school mathematics. Our goal is to investigate features of instruction that might account for this phenomenon. Drawing on a case study of two high school algebra teachers, we cite episodes from the classroom to illustrate particular teaching actions that de-emphasize meaning. We categorize these actions as pertaining to (a) purpose of new concepts, (b) distinctions in mathematics, (c) mathematical terminology, and (d) mathematical symbols. The specificity of the actions that we identify allows us to suggest several conjectures as to the impact of the teaching practices observed on student learning: that students will develop the belief that mathematics involves executing standard procedures much more than meaning and reasoning, that students will come to see mathematical definitions and results as coincidental or arbitrary, and that students’ treatment of symbols will be largely non-referential.     

Are ‘misconceptions’ or alternative frameworks of force and motion spontaneous or formed prior to instruction?

It has often been assumed that misconceptions of force and motion are part of an alternative framework and that conceptual change takes place when that framework is challenged and replaced with the Newtonian framework. There have also been variations of this theme, such as this structure is not coherent and conceptual change does not involve the replacement of concepts, conceptions or ideas but consists of the development of scientific ideas that can exist alongside ideas of the everyday. This article argues that misconceptions (or preconceptions, intuitive ideas, synthetic models, p-prims etc.) may not be formed until the learner considers force and motion within the learning situation and reports on a classroom observation (that is replicated with similar results) that suggest misconceptions arise, not because of prior experience, but spontaneously in the attempt at making sense of the terms of the discourse. The implications are that misconceptions may not be preformed, that research ought to consider the possible spontaneity in the students’ reasoning and then, if possible, attempt to discern any preformed elements or antecedents, and that we ought to reconsider what is meant by ‘conceptual change’. The classroom observation also suggests gravity as a particular stumbling-block for students. The implications for further research are discussed.     

Scheduling Classes on a College Campus

We consider the problem of scheduling a set of classes to classrooms with the objective of minimizing the number of classrooms used. The major constraint that we must obey is that no two classes can be assigned to the same classroom at the same time on the same day of the week. We present an algorithm that produces a nearly optimal schedule for an arbitrary set of classes. The algorithm's first stage produces a packing of classes using a combination of a greedy algorithm and a non-bipartite matching and the second stage consists of a bipartite matching.First we show that for one variant of the problem our algorithm produces schedules that require a number of classrooms that is always within a small additive constant of optimal. Then we show that for an interesting variant of the problem the same algorithm produces schedules that require a small constant factor more classrooms than optimal. Finally, we report on experimental results of our algorithm using actual data and also show how to create schedules with other desirable characteristics.     

Bruck–Reilly extensions of direct products of monoids and completely (0-)simple semigroups

We say that a class of monoids satisfies the property ℘ if every monoid in that class that admits a finitely presented Bruck–Reilly extension is finitely generated. We show that completely (0-)simple semigroups satisfy ℘, and that the direct product of two monoids in a class that satisfy ℘ also satisfies ℘ subject to a certain condition on the endomorphisms of the direct product. As a consequence of this result we obtain a new class of bands and a new class of completely regular semigroups that satisfy property ℘.     

The deterministic EOQ with partial backordering: A new approach

Previous authors have shown that if demand that cannot be filled from stock is partially backordered, then using the full-backordering model or assuming that all stockouts will result in lost sales can lead to substantial increases in cost relative to using a model that specifically recognizes the percentage of the stockouts that will be backordered. The models that these authors developed resulted in procedures or equations that are relatively difficult to use. In this paper we take a different approach to modeling the deterministic EOQ with partial backordering that results in equations that are more like the comparable equations for the basic EOQ and its full-backordering extension.