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Articles 24931 - 24960 of 27391

Full-Text Articles in Physical Sciences and Mathematics

Activator-Inhibitor Control Of Tissue Growth, John A. Adam Jan 1991

Activator-Inhibitor Control Of Tissue Growth, John A. Adam

Mathematics & Statistics Faculty Publications

This note develops a simple model for the competition between activator and inhibitor control mechanisms in one-dimensional tissue growth. The pedagogic usefulness of such a model is that it is easily accessible to undergraduate applied mathematicians and is suggestive of behavior known to occur in more realistic biological systems (e.g., some types of cancer). The limitations of the model are obvious and can provide a basis for discussion of the applicability of complementary levels of description in mathematical modeling.


A New Model Of The Molecular Bond, Donald Greenspan Jan 1991

A New Model Of The Molecular Bond, Donald Greenspan

Mathematics Technical Papers

It is assumed, on the basis of recent supercomputer calculations, that electrons attract, rather than repel. The consequences are explored by means of three dimensional, molecular mechanics type simulations of ground state [see pdf for notation]. Using spectroscopic data, it is shown that, in every case, the resulting vibrational frequencies and molecular diameters are entirely in agreement with experiment.


Best Lp Aapproximation With Multiple Constraints For 1 ⩽ P < ∞, J. J. Swetits, S. E. Weinstein, Yuesheng Xu Jan 1991

Best Lp Aapproximation With Multiple Constraints For 1 ⩽ P < ∞, J. J. Swetits, S. E. Weinstein, Yuesheng Xu

Mathematics & Statistics Faculty Publications

The problem considered in this paper is best Lp approximation with multiple constraints for 1 ⩽ p < ∞. Characterizations of best Lp approximations from multiple n-convex splines and functions are established and the relationship between them is investigated. Applications to best monotone convex approximation are studied.


Foundations Of Fuzzy Sets, Lawrence Stout, Ulrich Höhle Dec 1990

Foundations Of Fuzzy Sets, Lawrence Stout, Ulrich Höhle

Lawrence N. Stout

This paper gives an overview of the origins of fuzzy set theory and the problems for the foundations of fuzzy sets arising from those origins and current practice. It then gives detailed accounts of categorical approaches using a closed structure to capture the fuzzy AND connective. Within these categories weak forms of subobject representations provide an internal second order logic. An approach to fuzzy real numbers and fuzzy topology is included to illustrate the use of this internal; second order theory.


A Symmetric Porosity Conjecture Of Zajícek, Karen Saxe, P. Humke, M. Evans Dec 1990

A Symmetric Porosity Conjecture Of Zajícek, Karen Saxe, P. Humke, M. Evans

Karen Saxe

No abstract provided.


Reductions Of Graphs And Spanning Eulerian Subgraphs, Zhi-Hong Chen Dec 1990

Reductions Of Graphs And Spanning Eulerian Subgraphs, Zhi-Hong Chen

Zhi-Hong Chen

This dissertation is primarily focused on conditions for the existence of spanning closed trails in graphs. However, results in my dissertation and the method we used, which was invented by Catlin, are not only useful for finding spanning closed trails in graphs, but also useful to study double cycle cover problems, hamiltonian line graphs problems, and dominating closed trail problems, etc. A graph is called supereulerian if it contains a spanning closed trail. Several, people have worked on the conditions for spanning closed trails having the form "d(u) + d(v) $>$ cn (0 $<$ c $<$ 1)" for all edge …


A Survey Of Fuzzy Set And Topos Theory, Lawrence Stout Dec 1990

A Survey Of Fuzzy Set And Topos Theory, Lawrence Stout

Lawrence N. Stout

This paper is a comparison and contrast of approaches to many-valued mathematics offered by Fuzzy Set theory and topos theory. It gives a survey of the categorical foundations of Fuzzy Set theory and related topoi. Topoi are not a basis for Fuzzy Set theory but they do suggest appropriate directions to go and questions to ask for a synthesis which does provide a foundation. One possible structure which has a topos-like internal logic and the, rich variety of logical connectives used in fuzzy sets is included.


Asymptotic Behavior Of Solutions Of Functionally Perturbed Nonoscillatory Second Order Differential Equations, William F. Trench Dec 1990

Asymptotic Behavior Of Solutions Of Functionally Perturbed Nonoscillatory Second Order Differential Equations, William F. Trench

William F. Trench

No abstract provided.


Search Designs And Other Topic In Fractional Replication., Kashinath Chatterjee Dr. Dec 1990

Search Designs And Other Topic In Fractional Replication., Kashinath Chatterjee Dr.

Doctoral Theses

This thesis primarily deals with search designs (see Srivastava (1975)) of various types for general symmetric and asymmetric factorials. The thesis also considers some other types on fractional factorials. We have made use of Kronecker products and various other results from matrix theory.In the first four chapters, different types of search designs have been studied. Chapter 5A considers the construction of orthogonal main-effect plans for general factorial experiments under the presence of a linear time trend. Chapter 5B extends the calculus for factorial arrangements to a fractional factorial set-up and examines critically the proportional frequency plans from the point of …


Notes On Sufficient Conditions For A Graph To Be Hamiltonian, Michael Joseph Paul, Carmen Baytan Shershin, Anthony Connors Shershin Dec 1990

Notes On Sufficient Conditions For A Graph To Be Hamiltonian, Michael Joseph Paul, Carmen Baytan Shershin, Anthony Connors Shershin

School of Computing and Information Sciences

The first part of this paper deals with an extension of Dirac's Theorem to directed graphs. It is related to a result often referred to as the Ghouila-Houri Theorem. Here we show that the requirement of being strongly connected in the hypothesis of the Ghouila-Houri Theorem is redundant.

The Second part of the paper shows that a condition on the number of edges for a graph to be hamiltonian implies Ore's condition on the degrees of the vertices.


A Nonstandard Delta Function, Todor D. Todorov Dec 1990

A Nonstandard Delta Function, Todor D. Todorov

Mathematics

We prove that the Dirac delta distribution has a kernel in the class of the pointwise nonstandard functions.


Generalized Gradient Methods For Solving Locally Lipschitz Feasibility Problems, Dan Butnariu Dec 1990

Generalized Gradient Methods For Solving Locally Lipschitz Feasibility Problems, Dan Butnariu

Mathematics Technical Papers

In this paper we study the behavior of a class of iterative algorithms for solving feasibility problems, that is finite systems of inequalities [see pdf for notation], where each [see pdf for notation] is a locally Lipschitz functional on a Hilbert space X. We show that, under quite mild conditions, the algorithms studied in this note, if converge, then they approximate a solution of the feasibility given problem, provided that the feasibility problem is consistent. We prove several convergence criteria showing that, when the envelope of the functionals [see pdf for notation], is sufficiently "regular", then the algorithms converge. The …


A Method For Approximating The Solution Set Of A System Of Convex Inequalities By Polytopes, Yair Censor, Dan Butnariu Dec 1990

A Method For Approximating The Solution Set Of A System Of Convex Inequalities By Polytopes, Yair Censor, Dan Butnariu

Mathematics Technical Papers

In this note a method for computing approximations by polytopes of the solution set [see pdf for notation] of a system of convex inequalities is presented. It is shown that such approximations can be determined by an algorithm which converges in finitely many steps when the solution set of the given system of inequalities is bounded. In this case, the algorithm generates "inner" and "outer' approximations having the Hausdorff distance to each other (and to the set [see pdf for notation]) not greater than an a priori fixed [see pdf for notation] and having their extremal points in [see pdf …


Studies In Rapid Kinetic Reactions By Quasi-Quantum Mechanical, Conservative Methodology, Donald Greenspan Dec 1990

Studies In Rapid Kinetic Reactions By Quasi-Quantum Mechanical, Conservative Methodology, Donald Greenspan

Mathematics Technical Papers

Simulations are made of prototype, ground state, rapid kinetic reactions for A+BC, in which B, and C are hydrogen atoms and BC is a hydrogen molecule. We study cases in which B and C first unbind, and then A, B, and C undergo complex, three-body, oscillatory behavior in accordance with the Morse potential. It is shown that, in every case, one of A, or C is ejected and the remaining two atoms form an H2 bond with precisely correct ground state energy, frequency, and bond length. Pico second trajectories are described and discussed. The numerical method employed conserves the system's …


Dihedral Rewriteability, Cheryl P. Grood Nov 1990

Dihedral Rewriteability, Cheryl P. Grood

Mathematical Sciences Technical Reports (MSTR)

In this paper we compute the probability that an n-tuple for a group G is S-rewritable for a given set S of permutations for several classes of groups.


Some Facts About Cwat-Sets, Martin Wattenburg Nov 1990

Some Facts About Cwat-Sets, Martin Wattenburg

Mathematical Sciences Technical Reports (MSTR)

In [1] and [2], Sherman and Atkins, in connection with a problem in statistics, introduced a generalization of the concept of a subgroup of Z2. These generalized subgroups, which we call CWAT-sets (where "CWAT" is an acronym for "Closed With A Twist" ), have a rich algebraic structure. In this paper we establish some simple combinatorial facts about CWAT-sets, as well as provide two construction methods, prove a divisibility theorem, and make a classification conjecture.


Accurate Quasi-Quantum Mechanical Numerical Methodology, Donald Greenspan Oct 1990

Accurate Quasi-Quantum Mechanical Numerical Methodology, Donald Greenspan

Mathematics Technical Papers

A quasi-quantum mechanical method in which energy is determined by quantum mechanics and motion by Newtonian mechanics is studied by combining it with numerical methodology which conserves energy exactly at each time step. Application is made to the study of the diameter and vibrational frequency of the ground state H2 molecule. The numerical results agree exactly with experimental and quantum mechanical results.


Degree Of Adaptive Approximation, Ronald A. Devore, Ming Yu Xiang Oct 1990

Degree Of Adaptive Approximation, Ronald A. Devore, Ming Yu Xiang

Faculty Publications

We obtain various estimates for the error in adaptive approximation and also establish a relationship between adaptive approximation and free-knot spline approximation.


Mathematical Visions: The Pursuit Of Geometry In Victorian England (Book Review), Calvin Jongsma Sep 1990

Mathematical Visions: The Pursuit Of Geometry In Victorian England (Book Review), Calvin Jongsma

Faculty Work Comprehensive List

Reviewed Title: Joan L. Richards. Mathematical Visions: The Pursuit of Geometry in Victorian England. xiii + 266 pp., illus., figs., bibl., index. Boston/New York: Academic Press, Harcourt Brace Jovanovich, 1988.


A Numerical Approach To Rewriteability In Finite Groups, J.L. Leavitt, G.J. Sherman, M.E. Walker Sep 1990

A Numerical Approach To Rewriteability In Finite Groups, J.L. Leavitt, G.J. Sherman, M.E. Walker

Mathematical Sciences Technical Reports (MSTR)

In this paper we compute the probability that an n-tuple for a group G is S-rewritable for a given set S of permutations for several classes of groups.


Maximal Order Three-Rewriteable Subgroups Of Symmetric Groups, John T. O'Bryan Sep 1990

Maximal Order Three-Rewriteable Subgroups Of Symmetric Groups, John T. O'Bryan

Mathematical Sciences Technical Reports (MSTR)

Recently, Burns and Goldsmith [2] characterized the maximal order Abelian subgroups of the symmetric groups using elementary techniques and the results of Hoffman [5]. This classification could also be directly inferred from the results of Kovacs and Praeger [7]. A natural extension would be to consider the weaker, more general form of commutativity, three-rewriteability. The purpose of this paper is to completely characterize the maximal order three-rewriteable subgroups of the symmetric groups.


How Hamiltonian Can A Finite Group Be?, G.J. Sherman, T.J. Tucker, M.E. Walker Sep 1990

How Hamiltonian Can A Finite Group Be?, G.J. Sherman, T.J. Tucker, M.E. Walker

Mathematical Sciences Technical Reports (MSTR)

No abstract provided.


Fibonacci Sequences In Finite Groups, Steven W. Knox Sep 1990

Fibonacci Sequences In Finite Groups, Steven W. Knox

Mathematical Sciences Technical Reports (MSTR)

This paper extend the notion of Fibonacci sequence mod m to Fibonacci sequences in finite groups.


Sets Of Typical Subsamples, Joel Atkins, G.J Sherman Sep 1990

Sets Of Typical Subsamples, Joel Atkins, G.J Sherman

Mathematical Sciences Technical Reports (MSTR)

A group theoretic condition on a set of subsamples of a random sample from a continuous random variable symmetric about 0 is shown to be sufficient to provide typical values for 0.


Berry-Esseen-Type Bounds For Signed Linear Rank Statistics With A Broad Range Of Scores, Munsup Seoh Sep 1990

Berry-Esseen-Type Bounds For Signed Linear Rank Statistics With A Broad Range Of Scores, Munsup Seoh

Mathematics and Statistics Faculty Publications

The Berry-Esseen-type bounds of order N−1/2 for the rate of convergence to normality are derived for the signed linear rank statistics under the hypothesis of symmetry. The results are obtained with a broad range of regression constants and scores (allowed to be generated by discontinuous score generating functions, but not necessarily) restricted by only mild conditions, while almost all previous results are obtained with continuously differentiable score generating functions. Furthermore, the proof is very short and elementary, based on the conditioning argument.


Supercomputer Simulation Of The Modes Of Colliding Microdrops Of Water, Larry F. Heath, Donald Greenspan Sep 1990

Supercomputer Simulation Of The Modes Of Colliding Microdrops Of Water, Larry F. Heath, Donald Greenspan

Mathematics Technical Papers

No abstract provided.


Notions Of Relative Ubiquity For Invariant Sets Of Relational Structures, Paul Bankston, Wim Ruitenburg Sep 1990

Notions Of Relative Ubiquity For Invariant Sets Of Relational Structures, Paul Bankston, Wim Ruitenburg

Mathematics, Statistics and Computer Science Faculty Research and Publications

Given a finite lexicon L of relational symbols and equality, one may view the collection of all L-structures on the set of natural numbers w as a space in several different ways. We consider it as: (i) the space of outcomes of certain infinite two-person games; (ii) a compact metric space; and (iii) a probability measure space. For each of these viewpoints, we can give a notion of relative ubiquity, or largeness, for invariant sets of structures on w. For example, in every sense of relative ubiquity considered here, the set of dense linear orderings on w is …


Rewriteable Sequencings Of Groups, Jeanne Nielsen Aug 1990

Rewriteable Sequencings Of Groups, Jeanne Nielsen

Mathematical Sciences Technical Reports (MSTR)

A finite group is called Pn-sequenceable if its nonidentity elements can be listed x1 , x2 , ..., xk so that the product x i x i+i · · · x i+n-1 can be rewritten in at least one nontrivial way for all i. It is shown that Sn , An , Dn are P3-sequenceable, that every finite simple group is P4 -sequenceable, and that every finite group is Ps-sequenceable. It is conjectured that every finite group is P3-sequenceable.


Sums Of Semiprime, Z, And D L-Ideals In A Class Of F-Rings, Suzanne Larson Aug 1990

Sums Of Semiprime, Z, And D L-Ideals In A Class Of F-Rings, Suzanne Larson

Mathematics, Statistics and Data Science Faculty Works

In this paper it is shown that there is a large class of f-rings in which the sum of any two semiprime i-ideals is semiprime. This result is used to give a class of commutative f-rings with identity element in which the sum of any two z-ideals which are i-ideals is a z-ideal and the sum of any two d-ideals is a d-ideal.


Some Np-Complete Problems In Linear Algebra, Santhosh Sastry '90 Jul 1990

Some Np-Complete Problems In Linear Algebra, Santhosh Sastry '90

Honors Projects

This research project is aimed at studying the theory of NP-Completeness and determining the complexity of certain problems in linear algebra. The first chapter introduces the reader to Complexity theory and defines NP-Completeness. It is supported by Appendices 1 and 2. Appendix 3 lists some known NP-Complete problems.