Archive for Lucien Le Cam
Marseille mais non Marseille!
Posted in Kids, Mountains, pictures, Statistics, Travel, University life with tags conference, Judith Rousseau, Lucien Le Cam, Marseiile, Mediterranean Sea, Mont Puget, Pierre Simon de Laplace, Saint-Charles, SFDS, Université Aix Marseille, Vieux-Port on June 2, 2025 by xi'an
Borel and Langevin jailed [in 1941]
Posted in Books, Kids, pictures, Statistics, University life with tags Abwehr, Académie des Sciences, anti-fascism, Camille Marbo, collaboration, Collège de France, Emile Borel, French Navy, French resistance, IHP, Institut Henri Poincaré, Jacques Solomon, Lucien Le Cam, Nazi occupation, Paul Langevin, Pétain, Vichy régime, WW II on December 1, 2024 by xi'an
When attending the Le Cam 100th anniversary day at IHP, I learned from Laurent Mazliak’s talk that Émile Borel Borel (then in his 70’s and a member of the French Académie des Sciences) was arrested and jailed for a few weeks in 1941, as well as Paul Langevin (both in 1940 and 1941), for political (left-wing) reasons (?), by German security services (Abwehr), with no involvement of the French collaborationist authorities who rather intervened towards their release (along with the German Navy!, unlikely connected with Borel being the minister of the French Navy in 1924!!). Possibly from denunciations sent to German forces. Possibly as a show of power by the occupying forces towards the Vichy government and Philippe Pétain. The fact that Borel and his wife, Camille Marbo, were actually engaged in the French Resistance at least from 1942 fortunately did not come to the knowledge of French police or German security. (Langevin was one of the founders of the 1934 Comité de vigilance des intellectuels antifascistes. In 1941, his son-in-law, Jacques Solomon, a physicist, got arrested and executed for founding a clandestine newspaper, l’Université libre. His daughter Hélène Solomon-Langevin got deported but survived several deportation camps.)
Le Cam à l’Institut Henri Poincaré
Posted in pictures, Running with tags 10th international Purdue symposium on Statistics, asymptotics, colloquium, conference, France, Institut Henri Poincaré, LPSM, Lucien Le Cam, Paris, Pitman nearness, Purdue University, SFDS, Statistical Decision Theory and Related Topics on November 15, 2024 by xi'an
Colin Blyth (1922-2019)
Posted in Books, pictures, Statistics, University life with tags bagpipes, C.R. Rao, caligraphy, Canada, Colin Blyth, decision theory, discussion paper, Erich Lehmann, IMS Bulletin, JASA, La Trobe University, Lucien Le Cam, Melbourne, obituary, Ontario, Pitman nearness, Simpson's paradox, transitivity on March 19, 2020 by xi'an
While reading the IMS Bulletin (of March 2020), I found out that Canadian statistician Colin Blyth had died last summer. While we had never met in person, I remember his very distinctive and elegant handwriting in a few letters he sent me, including the above I have kept (along with an handwritten letter from Lucien Le Cam!). It contains suggestions about revising our Is Pitman nearness a reasonable criterion?, written with Gene Hwang and William Strawderman and which took three years to publish as it was deemed somewhat controversial. It actually appeared in JASA with discussions from Malay Ghosh, John Keating and Pranab K Sen, Shyamal Das Peddada, C. R. Rao, George Casella and Martin T. Wells, and Colin R. Blyth (with a much stronger wording than in the above letter!, like “What can be said but “It isn’t I, it’s you that are crazy?”). While I had used some of his admissibility results, including the admissibility of the Normal sample average in dimension one, e.g. in my book, I had not realised at the time that Blyth was (a) the first student of Erich Lehmann (b) the originator of [the name] Simpson’s paradox, (c) the scribe for Lehmann’s notes that would eventually lead to Testing Statistical Hypotheses and Theory of Point Estimation, later revised with George Casella. And (d) a keen bagpipe player and scholar.
maximum likelihood: an introduction
Posted in Books, Statistics with tags Bahadur, International Statistical Review, Likelihood Principle, Lucien Le Cam, maximum likelihood estimation on December 20, 2014 by xi'an“Basic Principle 0. Do not trust any principle.” L. Le Cam (1990)
Here is the abstract of a International Statistical Rewiew 1990 paper by Lucien Le Cam on maximum likelihood. ISR keeping a tradition of including an abstract in French for every paper, Le Cam (most presumably) wrote his own translation [or maybe wrote the French version first], which sounds much funnier to me and so I cannot resist posting both, pardon my/his French! [I just find “Ce fait” rather unusual, as I would have rather written “Ceci fait”…]:
Maximum likelihood estimates are reported to be best under all circumstances. Yet there are numerous simple examples where they plainly misbehave. One gives some examples for problems that had not been invented for the purpose of annoying maximum likelihood fans. Another example, imitated from Bahadur, has been specially created with just such a purpose in mind. Next, we present a list of principles leading to the construction of good estimates. The main principle says that one should not believe in principles but study each problem for its own sake.
L’auteur a ouï dire que la méthode du maximum de vraisemblance est la meilleure méthode d’estimation. C’est bien vrai, et pourtant la méthode se casse le nez sur des exemples bien simples qui n’avaient pas été inventés pour le plaisir de montrer que la méthode peut être très désagréable. On en donne quelques-uns, plus un autre, imité de Bahadur et fabriqué exprès pour ennuyer les admirateurs du maximum de vraisemblance. Ce fait, on donne une savante liste de principes de construction de bons estimateurs, le principe principal étant qu’il ne faut pas croire aux principes.
The entire paper is just as witty, as in describing the mixture model as “contaminated and not fit to drink”! Or in “Everybody knows that taking logarithms is unfair”. Or, again, in “biostatisticians, being complicated people, prefer to work out not with the dose y but with its logarithm”… And a last line: “One possibility is that there are too many horse hairs in e”.
