Early death
Suffering from chronic liver problems, Ramsey developed jaundice(黄疸になる:developに(病気に)なるって意味があるのか？英辞郎だと問題が生じる) after an abdominal operation(abdominalは腹部の。開腹手術らしい) and died on 19 January 1930 at Guy's Hospital in London at the age of 26.
He is buried in the Parish of the Ascension Burial Ground in Cambridge; his parents are buried in the same plot.[11]
Ramsey's notes and manuscripts were acquired by Nicholas Rescher for the Archives of Scientific Philosophy and the University of Pittsburgh. This collection contains only a few letters but a great many drafts of papers and book chapters, some still unpublished. Other papers, including his diary and letters and memoirs by his widow Lettice Ramsey and his father, are held in the Modern Archives, King's College, Cambridge.
The Decision Analysis Society[12] annually awards the Frank P. Ramsey Medal[13] to recognise substantial contributions to decision theory and its application to important classes of real decision problems.
Work
Mathematical logic
One of the theorems proved by Ramsey in his 1928 paper On a problem of formal logic now bears his name (Ramsey's theorem). While this theorem is the work Ramsey is probably best remembered for, he only proved it in passing, as a minor lemma along the way to his true goal in the paper, solving a special case of the decision problem for first-order logic, namely the decidability of what is now called the Bernays?Schonfinkel?Ramsey class of first-order logic, as well as a characterisation of the spectrum of sentences in this fragment of logic. Alonzo Church would go on to show that the general case of the decision problem for first-order logic is unsolvable (see Church's theorem). A great amount of later work in mathematics was fruitfully developed out of the ostensibly minor lemma, which turned out to be an important early result in combinatorics, supporting the idea that within some sufficiently large systems, however disordered, there must be some order. So fruitful, in fact, was Ramsey's theorem that today there is an entire branch of mathematics, known as Ramsey theory, which is dedicated to studying similar results.
Philosophy
His philosophical works included Universals (1925), Facts and propositions (1927) (which proposed a redundancy theory of truth), Universals of law and of fact (1928), Knowledge (1929), Theories (1929), On Truth (1929), and General propositions and causality (1929). Wittgenstein mentions him in the introduction to his Philosophical Investigations as an influence.
Economics
Keynes and Pigou encouraged Ramsey to work on economics as "From a very early age, about sixteen I think, his precocious mind was intensely interested in economic problems" (Keynes, 1933). Ramsey responded to Keynes's urging by writing three papers in economic theory all of which were of fundamental importance, though it was many years before they received their proper recognition by the community of economists.
Ramsey's three papers, described below in detail, were on subjective probability and utility (1926), optimal allocation (1927) and optimal one-sector economic growth (1928). The economist Paul Samuelson described them in 1970 as "three great legacies ? legacies that were for the most part mere by-products of his major interest in the foundations of mathematics and knowledge."[14]
A mathematical theory of saving
This significant paper was published in The Economic Journal, and involved "a strategically beautiful application of the calculus of variations" (Paul Samuelson)[15] to determine the optimal amount an economy should invest (save) rather than consume so as to maximise future utility, or in Ramsey's words "how much of its income should a nation save?" (Ramsey, 1928).
Keynes described the article as "one of the most remarkable contributions to mathematical economics ever made, both in respect of the intrinsic importance and difficulty of its subject, the power and elegance of the technical methods employed, and the clear purity of illumination with which the writer's mind is felt by the reader to play about its subject. The article is terribly difficult reading for an economist, but it is not difficult to appreciate how scientific and aesthetic(審美眼・審美眼のある esθ[e]tik) qualities are combined in it together."[16] The Ramsey model is today acknowledged as the starting point for optimal accumulation theory although its importance was not recognised until many years after its first publication.
The main contributions of the model were firstly the initial question Ramsey posed on how much savings should be and secondly the method of analysis, the intertemporal maximisation (optimisation) of collective or individual utility by applying techniques of dynamic optimisation. Tjalling C. Koopmans and David Cass modified the Ramsey model incorporating the dynamic features of population growth at a steady rate and of Harrod-neutral technical progress again at a steady rate, giving birth to a model named the Ramsey?Cass?Koopmans model where the objective now is to maximise household's utility function.
A Contribution to the Theory of Taxation
Author(s): F. P. Ramsey
Source: The Economic Journal, Vol. 37, No. 145 (Mar., 1927), pp. 47-61 https://www.jstor.org/stable/pdf/2222721.pdf
A contribution to the theory of taxation
In this paper Ramsey's contribution to economic theory was the elegant concept of Ramsey pricing. This is applicable in situations where a (regulated) monopolist wants to maximise consumer surplus whilst at the same time ensuring that its costs are adequately covered. This is achieved by setting the price such that the markup over marginal cost is inversely proportional to the price elasticity of demand for that good. Like its predecessor this paper was published in The Economic Journal in 1927. Ramsey poses the question that is to be solved at the beginning of the article: "a given revenue is to be raised by proportionate taxes on some or all uses of income, the taxes on different uses being possibly at different rates; how much should these rates be adjusted in order that the decrement of utility may be a minimum?" (Ramsey 1927). The problem was suggested to him by the economist Arthur Pigou and the paper was Ramsey's answer to the problem.
Truth and probability
Keynes in his A Treatise on Probability (1921) argued against the subjective approach in epistemic probabilities. For Keynes, subjectivity of probabilities doesn't matter as much, as for him there is an objective relationship between knowledge and probabilities, as knowledge is disembodied and not personal.
Ramsey in his article disagrees with Keynes's approach as for him there is a difference between the notions of probability in physics and in logic. For Ramsey probability is not related to a disembodied body of knowledge but is related to the knowledge that each individual possesses alone. Thus personal beliefs that are formulated by this individual knowledge govern probabilities, leading to the notions of subjective probability and Bayesian probability. Consequently, subjective probabilities can be inferred by observing actions that reflect individuals' personal beliefs. Ramsey argued that the degree of probability that an individual attaches to a particular outcome can be measured by finding what odds the individual would accept when betting on that outcome.
Ramsey suggested a way of deriving a consistent theory of choice under uncertainty that could isolate beliefs from preferences while still maintaining subjective probabilities.
Despite the fact that Ramsey's work on probabilities was of great importance again no one paid any attention to it until the publication of Theory of Games and Economic Behavior of John von Neumann and Oskar Morgenstern in 1944 (1947 2nd ed.)
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65537 は {\displaystyle 2^{2^{4}}+1}2^{{2^{4}}}+1 の形で表され、2018年2月現在知られているうちで最大のフェルマー素数である。カール・フリードリヒ・ガウスは1801年に出版した『整数論の研究』において、p がフェルマー素数ならば正 p 角形は定規とコンパスで作図可能であることを証明した。また、逆に、奇素数 p に対して正 p 角形が作図可能ならば、p はフェルマー素数であることも証明した
