Studies in the History of Mathematics and Physical Sciences – Serie

In this book I have attempted to trace the development of numerical analysis during the period in which the foundations of the modern theory were being laid. To do this I have had to exercise a certain amount of selectivity in choosing and in rejecting both authors and papers. I have rather arbitrarily chosen, in the main, the most famous mathematicians of the period in question and have concentrated on their major works in numerical analysis at the expense, perhaps, of other lesser known but capable analysts. This selectivity results from the need to choose from a large body of literature, and from my feeling that almost by definition the great masters of mathematics were the ones responsible for the most significant accomplishments. In any event I must accept full responsibility for the choices. I would particularly like to acknowledge my thanks to Professor Otto Neugebauer for his help and inspiration in the preparation of this book. This consisted of many friendly discussions that I will always value. I should also like to express my deep appreciation to the International Business Machines Corporation of which I have the honor of being a Fellow and in particular to Dr. Ralph E. Gomory, its Vice-President for Research, for permitting me to undertake the writing of this book and for helping make it possible by his continuing encouragement and support.

The Russian edition of this book appeared in 1976 on the hundred-and-fiftieth anniversary of the historic day of February 23, 1826, when LobaeevskiI delivered his famous lecture on his discovery of non-Euclidean geometry. The importance of the discovery of non-Euclidean geometry goes far beyond the limits of geometry itself. It is safe to say that it was a turning point in the history of all mathematics. The scientific revolution of the seventeenth century marked the transition from "mathematics of constant magnitudes" to "mathematics of variable magnitudes. " During the seventies of the last century there occurred another scientific revolution. By that time mathematicians had become familiar with the ideas of non-Euclidean geometry and the algebraic ideas of group and field (all of which appeared at about the same time), and the (later) ideas of set theory. This gave rise to many geometries in addition to the Euclidean geometry previously regarded as the only conceivable possibility,to the arithmetics and algebras of many groups and fields in addition to the arith­ metic and algebra of real and complex numbers, and, finally, to new mathe­ matical systems, i. e. , sets furnished with various structures having no classical analogues. Thus in the 1870's there began a new mathematical era usually called, until the middle of the twentieth century, the era of modern mathe­ matics.

Kepler's Physical Astronomy is an account of Kepler's reformulation of astronomy as a physical science, and of his successful use of (incorrect) physics as a guide in his astronomical discoveries. It presents the only reliable account of the internal logic of Kepler's so-called first and second laws, showing how and to what extent Kepler thought he had derived them from his physical principles. It explains for the first time Kepler's attempt to use an obscure discovery of Tycho Brahe to unify and confirm all of his own physical theories. It also describes the intricate (and neglected) theory which Kepler developed to account for the additional anomalies needed for the theory of the moon.

Joseph Liouville was the most important French mathematician in the gen- eration between Galois and Hermite. This is reflected in the fact that even today all mathematicians know at least one of the more than six theorems named after him and regularly study Liouville's Journal, as the Journal de Mathematiques pures et appliquees is usually nicknamed after its creator. However, few mathematicians are aware of the astonishing variety of Liou- ville's contributions to almost all areas of pure and applied mathematics. The reason is that these contributions have not been studied in their histor- ical context. In the Dictionary of Scientific Biography 1973, Taton [1973] gave a rather sad but also true picture of the Liouville studies carried out up to that date: The few articles devoted to Liouville contain little biographical data. Thus the principal stages of his life must be reconstructed on the ba- sis of original documentation. There is no exhausti ve list of Liou ville's works, which are dispersed in some 400 publications ...His work as a whole has been treated in only two original studies of limited scope those of G. Chrystal and G. Loria.Since this was written, the situation has improved somewhat through the publications of Peiffer, Edwards, Neuenschwander, and myself. Moreover, C. Houzel and I have planned on publishing Liouville's collected works.

Ptolemy's Almagest shares with Euclid's Elements the glory of being the scientific text longest in use. From its conception in the second century up to the late Renaissance, this work determined astronomy as a science. During this time the Almagest was not only a work on astronomy; the subject was defined as what is described in the Almagest. The cautious emancipation of the late middle ages and the revolutionary creation of the new science in the 16th century are not conceivable without reference to the Almagest. This text lifted European astronomy to the high standard of knowledge on which the new science flourished. Before, the Ptolemaic models of the orbits of the sun, the moon, and the planets had been refined by Arabic astronomers. They provided the structural elements with which Copernicus and Kepler ushered in the era of modern astronomy. The Almagest survived the destruction of its epicyclic representation of the planetary orbits in the conceptual traces left behind in the theories of its successors. The clear separation of the sidereal from the tropical year, the celestial coordinate systems, the concepts of time, the forms of the constellations, and brightness classifications of celestial objects are, among many other things, still part of the astronomical canon even today.

The Russian edition of this book appeared in 1976 on the hundred-and-fiftieth anniversary of the historic day of February 23, 1826, when LobaeevskiI delivered his famous lecture on his discovery of non-Euclidean geometry. The importance of the discovery of non-Euclidean geometry goes far beyond the limits of geometry itself. It is safe to say that it was a turning point in the history of all mathematics. The scientific revolution of the seventeenth century marked the transition from "mathematics of constant magnitudes" to "mathematics of variable magnitudes. " During the seventies of the last century there occurred another scientific revolution. By that time mathematicians had become familiar with the ideas of non-Euclidean geometry and the algebraic ideas of group and field (all of which appeared at about the same time), and the (later) ideas of set theory. This gave rise to many geometries in addition to the Euclidean geometry previously regarded as the only conceivable possibility,to the arithmetics and algebras of many groups and fields in addition to the arith­ metic and algebra of real and complex numbers, and, finally, to new mathe­ matical systems, i. e. , sets furnished with various structures having no classical analogues. Thus in the 1870's there began a new mathematical era usually called, until the middle of the twentieth century, the era of modern mathe­ matics.

Joseph Liouville was the most important French mathematician in the gen- eration between Galois and Hermite. This is reflected in the fact that even today all mathematicians know at least one of the more than six theorems named after him and regularly study Liouville's Journal, as the Journal de Mathematiques pures et appliquees is usually nicknamed after its creator. However, few mathematicians are aware of the astonishing variety of Liou- ville's contributions to almost all areas of pure and applied mathematics. The reason is that these contributions have not been studied in their histor- ical context. In the Dictionary of Scientific Biography 1973, Taton [1973] gave a rather sad but also true picture of the Liouville studies carried out up to that date: The few articles devoted to Liouville contain little biographical data. Thus the principal stages of his life must be reconstructed on the ba- sis of original documentation. There is no exhausti ve list of Liou ville's works, which are dispersed in some 400 publications ...His work as a whole has been treated in only two original studies of limited scope those of G. Chrystal and G. Loria.Since this was written, the situation has improved somewhat through the publications of Peiffer, Edwards, Neuenschwander, and myself. Moreover, C. Houzel and I have planned on publishing Liouville's collected works.

Ptolemy's Almagest shares with Euclid's Elements the glory of being the scientific text longest in use. From its conception in the second century up to the late Renaissance, this work determined astronomy as a science. During this time the Almagest was not only a work on astronomy; the subject was defined as what is described in the Almagest. The cautious emancipation of the late middle ages and the revolutionary creation of the new science in the 16th century are not conceivable without reference to the Almagest. This text lifted European astronomy to the high standard of knowledge on which the new science flourished. Before, the Ptolemaic models of the orbits of the sun, the moon, and the planets had been refined by Arabic astronomers. They provided the structural elements with which Copernicus and Kepler ushered in the era of modern astronomy. The Almagest survived the destruction of its epicyclic representation of the planetary orbits in the conceptual traces left behind in the theories of its successors. The clear separation of the sidereal from the tropical year, the celestial coordinate systems, the concepts of time, the forms of the constellations, and brightness classifications of celestial objects are, among many other things, still part of the astronomical canon even today.

The calculus of variations is a subject whose beginning can be precisely dated. It might be said to begin at the moment that Euler coined the name calculus of variations but this is, of course, not the true moment of inception of the subject. It would not have been unreasonable if I had gone back to the set of isoperimetric problems considered by Greek mathemati­ cians such as Zenodorus (c. 200 B. C. ) and preserved by Pappus (c. 300 A. D. ). I have not done this since these problems were solved by geometric means. Instead I have arbitrarily chosen to begin with Fermat's elegant principle of least time. He used this principle in 1662 to show how a light ray was refracted at the interface between two optical media of different densities. This analysis of Fermat seems to me especially appropriate as a starting point: He used the methods of the calculus to minimize the time of passage cif a light ray through the two media, and his method was adapted by John Bernoulli to solve the brachystochrone problem. There have been several other histories of the subject, but they are now hopelessly archaic. One by Robert Woodhouse appeared in 1810 and another by Isaac Todhunter in 1861.

When I first laid out the framework for A History of Ancient Mathe­ matical Astronomy, I intended to carry the discussion down to the last applications of Greek astronomical methodology, i. e. Copernicus, Brahe, and Kepler. But as the work proceeded, it became evident that this plan was much too ambitious, and so I decided to terminate my History with late antiquity, well before Islam. Nevertheless, I did not discard the running commentary that I had prepared when studying De revolutionibus in its relation to the methodology of the Almagest. Only recently, E. S. Kennedy and his collaborators had opened access to the" Maragha School" (mainly Ibn ash-Shalir), revealing close parallels to Copernicus's procedures. Accordingly, it seemed useful to make available a modern analysis of De revolutionibus, and thus in 1975 I prepared for publication "Notes on Copernicus. " In the meantime, however, Noel Swerdlow, also starting from Greek astronomy, not only extended his work into a deep analysis of De revolu­ tionibus, but also systematically investigated its sources and predecessors (Peurbach, Regiomontanus, etc. ). I was aware of these studies through his publications as well as from numerous conversations on the subject at The Institute for Advanced Study and at Brown University. It became clear to me that my own investigations lay at too superficial a level, and I therefore withdrew my manuscript and suggested to Swerdlow that he undertake a thoroughgoing revision and amplification of my "Notes. " His acceptance of my proposal initiated the present publication.

It would seem that S. Munk was the first modern scholar to draw attention to the significance of Levi ben Gerson's Astronomy, surely the most original work on astronomy written in Hebrew in the Middle Ages. Munk (1859, p. 500) called for a specialist to undertake a serious study of this work, but there was little response to his plea in the succeeding century. Indeed, this is the first edition of the Hebrew text of any part of Levi's Astronomy but for the table of contents (Renan, 1893, pp. 624-32), and the poems celebrating the invention of the Jacob Staff that appear in chapter 9 (Carlebach, 191Oa, pp. 152-53). The text of Levi's Astronomy is written in a ponderous Hebrew style but the content sparkles with originality. The Ptolemaic tradition is subjected to a profound critique based on the idea that the planetary models must conform both to Levi's own observations as well as those of the ancients, and the claim that astronomical theory must be philosophically sound. The enduring vigor of the Ptolemaic tradition has been characterized by O. Neugebauer as fol­ lows: "There is no better way to convince oneself of the inner coherence of ancient and medieval astronomy than to place side by side the Almagest, al­ BaWini's Opus astronomicum and Copernicus's De Revolutionibus. Chapter by chapter, theorem by theorem, table by table, these works run parallel" (1957, pp. 205-6).

Kepler's Physical Astronomy is an account of Kepler's reformulation of astronomy as a physical science, and of his successful use of (incorrect) physics as a guide in his astronomical discoveries. It presents the only reliable account of the internal logic of Kepler's so-called first and second laws, showing how and to what extent Kepler thought he had derived them from his physical principles. It explains for the first time Kepler's attempt to use an obscure discovery of Tycho Brahe to unify and confirm all of his own physical theories. It also describes the intricate (and neglected) theory which Kepler developed to account for the additional anomalies needed for the theory of the moon.

In this study we are concerned with Vibration Theory and the Problem of Dynamics during the half century that followed the publication of Newton's Principia. The relationship that existed between these subject!! is obscured in retrospection for it is now almost impossible not to view (linear) Vibration Theory as linearized Dynamics. But during the half century in question a theory of Dynamics did not exist; while Vibration Theory comprised a good deal of acoustical information, posed definite problems and obtained specific results. In fact, it was through problems posed by Vibration Theory that a general theory of Dynamics was motivated and discovered. Believing that the emergence of Dynamics is a critically important link in the history of mathematical science, we present this study with the primary goal of providing a guide to the relevant works in the aforemen­ tioned period. We try above all to make the contents of the works readily accessible and we try to make clear the historical connections among many of the pertinent ideas, especially those pertaining to Dynamics in many degrees of freedom. But along the way we discuss other ideas on emerging subjects such as Calculus, Linear Analysis, Differential Equations, Special Functions, and Elasticity Theory, with which Vibration Theory is deeply interwound. Many of these ideas are elementary but they appear in a surprising context: For example the eigenvalue problem does not arise in the context of special solutions to linear problems-it appears as a condition for isochronous vibrations.

I first learned the theory of distributions from Professor Ebbe Thue Poulsen in an undergraduate course at Aarhus University. Both his lectures and the textbook, Topological Vector Spaces, Distributions and Kernels by F. Treves, used in the course, opened my eyes to the beauty and abstract simplicity of the theory. However my incomplete study of many branches of classical analysis left me with the question: Why is the theory of distributions important? In my continued studies this question was gradually answered, but my growing interest in the history of mathematics caused me to alter my question to other questions such as: For what purpose, if any, was the theory of distributions originally created? Who invented distributions and when? I quickly found answers to the last two questions: distributions were invented by S. Sobolev and L. Schwartz around 1936 and 1950, respectively. Knowing this answer, however, only created a new question: Did Sobolev and Schwartz construct distributions from scratch or were there earlier trends and, if so, what were they? It is this question, concerning the pre­ history of the theory of distributions, which I attempt to answer in this book. Most of my research took place at the History of Science Department of Aarhus University. I wish to thank this department for its financial and intellectual support. I am especially grateful to Lektors Kirsti Andersen from the History of Science Department and Lars Mejlbo from the Mathematics Department, for their kindness, constructive criticism, and encouragement.

This book grew out of my interest in what is common to three disciplines: mathematics, philosophy, and history. The origins of Zermelo's Axiom of Choice, as well as the controversy that it engendered, certainly lie in that intersection. Since the time of Aristotle, mathematics has been concerned alternately with its assumptions and with the objects, such as number and space, about which those assumptions were made. In the historical context of Zermelo's Axiom, I have explored both the vagaries and the fertility of this alternating concern. Though Zermelo's research has provided the focus for this book, much of it is devoted to the problems from which his work originated and to the later developments which, directly or indirectly, he inspired. A few remarks about format are in order. In this book a publication is indicated by a date after a name; so Hilbert 1926, 178 refers to page 178 of an article written by Hilbert, published in 1926, and listed in the bibliography.

One of the pervasive phenomena in the history of science is the development of independent disciplines from the solution or attempted solutions of problems in other areas of science. In the Twentieth Century, the creation of specialties witqin the sciences has accelerated to the point where a large number of scientists in any major branch of science cannot understand the work of a colleague in another subdiscipline of his own science. Despite this fragmentation, the development of techniques or solutions of problems in one area very often contribute fundamentally to solutions of problems in a seemingly unrelated field. Therefore, an examination of this phenomenon of the formation of independent disciplines within the sciences would contrib­ ute to the understanding of their evolution in modern times. We believe that in this context the history of combinatorial group theory in the late Nineteenth Century and the Twentieth Century can be used effectively as a case study. It is a reasonably well-defined independent specialty, and yet it is closely related to other mathematical disciplines. The fact that combinatorial group theory has, so far, not been influenced by the practical needs of science and technology makes it possible for us to use combinatorial group theory to exhibit the role of the intellectual aspects of the development of mathematics in a clearcut manner. There are other features of combinatorial group theory which appear to make it a reasona­ ble choice as the object of a historical study.

Our interest in 1. J. Bienayme was kindled by the discovery of his paper of 1845 on simple branching processes as a model for extinction of family names. In this work he announced the key criticality theorem 28 years before it was rediscovered in incomplete form by Galton and Watson (after whom the process was subsequently and erroneously named). Bienayme was not an obscure figure in his time and he achieved a position of some eminence both as a civil servant and as an Academician. However, his is no longer widely known. There has been some recognition of his name work on least squares, and a gradually fading attribution in connection with the (Bienayme-) Chebyshev inequality, but little more. In fact, he made substantial contributions to most of the significant problems of probability and statistics which were of contemporary interest, and interacted with the major figures of the period. We have, over a period of years, collected his traceable scientific work and many interesting features have come to light. The present monograph has resulted from an attempt to describe his work in its historical context. Earlier progress reports have appeared in Heyde and Seneta (1972, to be reprinted in Studies in the History of Probability and Statistics, Volume 2, Griffin, London; 1975; 1976).