Saddle Point

The same problem, two schools

Two desks

The book's thesis is that the schools of game theory are different approaches to the same problems. Here are seven pairs who met one problem at different desks. Each desk is dated and sourced. What each knew of the other is stated only as far as the record goes, and the comparison of approaches is a reading, marked as such.

Kantorovich and Koopmans

The shared problem Allocating scarce resources under competing demands. R

Leonid V. Kantorovich, 1975
Leonid V. Kantorovich

1938–1939 · Leningrad · Leningrad University / plywood production problem

Studied production allocation and resolving multipliers.

Leonid Vital’evich Kantorovich (on his seventieth birthday), p. 232

Tjalling Koopmans

1942 · Washington, D.C. · British Merchant Shipping Mission

Studied cargo routing and its cost.

Tjalling Charles Koopmans, Biographical Memoirs 67, p. 275; pp. 280–282

What is documented

Correspondence is documented from 1956; earlier awareness remains unestablished here.

Still open. No dated record of their first knowledge of each other’s work has been found.

Leonid V. Kantorovich, Brief Biography, paragraph on correspondence with Koopmans in 1956

How the approaches differ Factory allocation and multipliers contrast with shipping routes and associated prices. R

Leonid Vital’evich Kantorovich (on his seventieth birthday), 37(3), pp. 229–238; Tjalling Charles Koopmans, Biographical Memoirs 67, p. 275; pp. 280–282

Different starting problems do not by themselves prove independent discovery.

Isaacs and Pontryagin

The shared problem Controlling motion when objectives compete. R

Rufus Isaacs

1954 · Santa Monica · RAND

Published the first Differential Games research memorandum.

Differential Games I: Introduction, RM-1391, 30 November 1954; pp. 1–6

Lev S. Pontryagin, c. 1950
Lev S. Pontryagin

mid-1950s · Moscow · Steklov Mathematical Institute

Developed the maximum principle with his collaborators.

On the history of discovery of the maximum principle, Abstract; pp. 1–7

What is documented

Isaacs later described an independent start and learning of control theory while completing his book. Pontryagin discusses and cites Isaacs’s 1965 book in a paper received on 8 April 1966: awareness on his side by 1966, not its first date.

Still open. The first date of awareness on Pontryagin’s side is not established.

Rufus Philip Isaacs and the Early Years of Differential Games, pp. 20–22; retrospective statement by Isaacs; К теории дифференциальных игр [On the theory of differential games], Uspekhi Matematicheskikh Nauk 21:4(130), pp. 219–274: introduction p. 219 explicitly discusses Isaacs’s 1965 book, which is reference 2 on p. 274

How the approaches differ Isaacs studied opposing controls; the maximum principle first supplied necessary conditions for optimal control. R

Differential Games I: Introduction, RM-1391, 30 November 1954; pp. 1–6; On the history of discovery of the maximum principle, Abstract; pp. 1–7

Isaacs’s recollection is evidence about his account, not proof of permanent mutual ignorance; the mathematical results are not identical.

Isaacs and Krasovskii

The shared problem Guaranteed outcomes in continuous pursuit. R

Rufus Isaacs

1954 · Santa Monica · RAND

Formulated pursuit games through the Main Equation.

Differential Games I: Introduction, RM-1391, 30 November 1954; pp. 1–6

Nikolai N. Krasovskii

late 1960s–early 1970s · Sverdlovsk · Ural State University / Institute of Mathematics and Mechanics

Developed positional strategies and guaranteed outcomes.

Nikolai Nikolaevich Krasovskii: on his eightieth birthday, p. 5

What is documented

Krasovskii cites the 1967 Russian translation of Isaacs’s Differential Games in a paper received on 6 April 1970: awareness on his side by 1970, not its first date.

Still open. The earliest awareness in either direction, and any awareness of Krasovskii on Isaacs’s side, are not established by the cited record.

О дифференциальной игре сближения [On a differential game of approach], Doklady Akademii Nauk SSSR 193(2), pp. 284–287; p. 287, reference 3 cites R. Isaacs, Differential Games, Moscow, 1967 (Russian translation)

How the approaches differ The comparison contrasts worked pursuit equations with feedback guarantees using stable sets and extremal aiming. R

Differential Games I: Introduction, RM-1391, 30 November 1954; pp. 1–6; Nikolai Nikolaevich Krasovskii: on his eightieth birthday, Trudy IMM 10(2), pp. 3–19; biography pp. 3–5

This describes emphases, not mutually exclusive methods or a proven independent-discovery claim.

Wald and Stratonovich

The shared problem Choosing well with limited information. R

Abraham Wald
Abraham Wald

1941 · New York · Columbia University

Reported his statistical decision-function research.

Columbia: Promotions and Memorial Minute for Abraham Wald, Annex B to the letter of 26 November 1941

Ruslan L. Stratonovich

1963–1965 · Moscow · Moscow State University

Lectured on information theory and its value.

Theory of Information and its Value: Foreword and Preface, Foreword, pp. vi–ix

Not established

The record cited here does not establish when either first knew of the other’s work.

How the approaches differ Statistical decision rules contrast with bounds on loss reduction under information constraints. R

Columbia: Promotions and Memorial Minute for Abraham Wald, Annex B to 26 November 1941 letter; Memorial Minute for Professor A. Wald; Theory of Information and its Value: Foreword and Preface, Foreword pp. v–xi; Preface p. xiii

This is a conceptual comparison, not a priority claim.

Brier and Savage

The shared problem Evaluating reported probabilities. R

Glenn W. Brier

1950 · Washington, D.C. · US Weather Bureau

Published a score for probability forecasts.

Verification of Forecasts Expressed in Terms of Probability, Monthly Weather Review 78(1), pp. 1–3; bibliographic record; The First International Statistical Climatology Achievement Award: Glenn W. Brier, Award remarks; 1958 recollection, 1950 scoring paper and 1955 cost/loss paper

Leonard J. Savage

1971 · New Haven · Yale University

Published Elicitation of Personal Probabilities and Expectations.

Elicitation of Personal Probabilities and Expectations, JASA 66(336), pp. 783–801; §§1.1–1.2, §2 and §6; Leonard Jimmie Savage Papers, MS 695, Guide compiled January 1974; biography p. 4; drafts p. 56 (current export)

What is documented

Savage reported initial unawareness of predecessors in 1960, but explicitly cited Brier in 1971.

Elicitation of Personal Probabilities and Expectations, p. 783, §1.1

How the approaches differ A quadratic forecast score contrasts with a broader analysis of truthful elicitation. R

Verification of Forecasts Expressed in Terms of Probability, Monthly Weather Review 78(1), pp. 1–3; bibliographic record; Elicitation of Personal Probabilities and Expectations, JASA 66(336), pp. 783–801; §§1.1–1.2, §2 and §6

The 1971 date is publication; it is not the date Savage first conceived elicitation.

Lefebvre and Harsanyi

The shared problem Representing beliefs about other participants. R

Vladimir A. Lefebvre

1967 · Moscow

Published Conflicting Structures.

Vladimir Aleksandrovich Lefebvre, Dated biographical paragraphs and list of publications

John C. Harsanyi

1967 · Berkeley · University of California, Berkeley

Published Part I of his Bayesian-games series.

Games with Incomplete Information Played by Bayesian Players, I–III. Part I: The Basic Model, Management Science 14(3), pp. 159–160 and §1

Not established

The record cited here does not establish when either first knew of the other’s work.

How the approaches differ Algebraic self-and-other representations contrast with probabilistic types for games with incomplete information. R

The Cosmism of Lefebvre’s Reflection: a conversation with V. A. Lefebvre, Psychology; Games with Incomplete Information Played by Bayesian Players, I–III. Part I: The Basic Model, Management Science 14(3), pp. 159–160 and §1

Moscow is the book’s publication place, not a verified physical writing desk. Similar questions do not establish an identical theory or influence.

Borel and von Neumann

The shared problem Randomisation in adversarial games. R

Émile Borel, 1918
Émile Borel

1921 · Paris · Académie des sciences

Published his first game note.

John von Neumann’s Conception of the Minimax Theorem: A Journey Through Different Mathematical Contexts, Archive for History of Exact Sciences 56, pp. 61–65, sections 6.1–6.2

John von Neumann, 1956
John von Neumann

December 1926 · Göttingen · Mathematical Institute

Presented game-theoretic work.

A History of the Minimax Theorem: von Neumann’s Conception of the Minimax Theorem, IMFUFA 387, §2; von Neumann’s 1928 footnote discussed there

What is documented

Von Neumann’s 1928 footnote dates his awareness of Borel to proofreading.

Still open. Borel’s first awareness date is not established here.

A History of the Minimax Theorem: von Neumann’s Conception of the Minimax Theorem, IMFUFA 387, §2; von Neumann’s 1928 footnote discussed there

How the approaches differ Small symmetric cases contrast with a general finite zero-sum minimax theorem. R

John von Neumann’s Conception of the Minimax Theorem: A Journey Through Different Mathematical Contexts, Archive for History of Exact Sciences 56, pp. 61–65, sections 6.1–6.2

A retrospective priority statement is not independent evidence of complete mutual ignorance.