Boris Weisfeiler

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Boris Weisfeiler (born April 19, 1941 in Moscow ; presumably died in Chile ) was a Russian-born American mathematician who has been missing in Chile since 1985 . There are several indications that forces of the Chilean military dictatorship , in cooperation with the Colonia Dignidad, forcibly "made him disappear ". After eight people were arrested in 2012 in connection with Weisfeiler's disappearance, the case was closed again in 2016 due to the statute of limitations. An appeal is currently being filed against this.

Life

Weisfeiler received his doctorate (candidate title) in 1970 at the Steklow Institute in Saint Petersburg with Ernest Borissowitsch Winberg . He emigrated to the United States in 1975 after his career was stalled for refusing to sign a petition against a colleague. He first worked at the Institute for Advanced Study with Armand Borel in 1975/76 and was later a professor at Pennsylvania State University . He had been a US citizen since 1981. As a mathematician, he has published over 30 papers, many of them on the theory of algebraic groups . Several mathematical concepts and a conjecture are named after him.

Weisfeiler was an experienced outdoor activist who liked to cross the wilderness alone, as he had in Siberia (he fled the Soviet Union on foot via Siberia), Alaska, China, Nepal and Peru, and set out on a mountain hike in the Chilean region on his own in late December 1984 Andes on. There he disappeared on January 5, 1985 near the vast area of Colonia Dignidad . Chilean policemen claimed he drowned. Weisfeiler, who spoke hardly any Spanish, had asked a shepherd for directions and showed him his destination on the map, a place near the south entrance of the Colonia. A brother of the shepherd saw him a short time later and notified the military police, which were sending out a patrol. His camouflage clothing aroused suspicion and the residents there had been instructed to report strangers to the police. According to their own statements, which were later checked on site by US consular officers, they found a backpack and footprints near a river and concluded that he had drowned while trying to cross.

To this day, however, rumors are being investigated that the Colonia Dignidad, in which there is evidence that critics of the regime were tortured in collaboration with the Chilean secret police, played a role in his disappearance. It has been suspected that he was arrested on suspicion of being a Soviet, "Jewish" or Israeli spy by a military patrol who took him to Colonia Dignidad, where he was murdered. Human rights activists in the USA around Weisfeiler's sister Olga (she immigrated to the USA) are still trying to clarify his fate. In 2006 they called for clarification from then Chilean President Michelle Bachelet in an open letter signed by 27 US Congressmen and US Senators . Olga Weisfeiler also met Bachelet personally in 2006 in Washington, DC .

In August 2012, eight former police and military officers were arrested and charged with kidnapping and forming a criminal organization in the Weisfeiler case. At the time, the police stated that because of his military clothing they had mistaken Weisfeiler for an illegally entered extremist who wanted to hide in Chile. That's why they caught him, arrested him and initially kept it a secret. The military later said that Weisfeiler drowned while crossing a river on the banks of which they had found traces of him.

The proceedings were discontinued in 2016 after the judge ruled that it was not a crime against humanity, but a "normal" crime, which is now statute barred. Boris' sister Olga Weisfeiler and other activists appealed the verdict and are seeking further investigation. In August 2017, the next hearing on the appeal was postponed again. The Chilean Mathematicians Association has also launched a campaign to reopen the case and resume investigations.

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His strong approximation theorem for the general linear group was widely used and establishes a connection between two topologies for subgroups of a linear group: If G is a Zariski - dense subgroup, this is also almost dense with regard to the congruence topology . The latter is a much stronger property that leads to a number of structural statements for algebraic groups. For the proof he used the results of the classification of finite simple groups , but now there are also proofs that circumvent this. In 1984 he also found the best bound for the index of Abelian normal subgroups of finite linear subgroups of the general linear group (the existence of such a bound was already known to Camille Jordan ). He also used the classification theorem of finite simple groups and was one of the first to apply this theorem, the proof of which is one of the high points of mathematics of the 20th century, to linear infinite groups in the early 1980s.

The Kac-Weisfeiler conjecture (also named after Victor Kac ) in the representation theory of Lie algebras over bodies with positive characteristics was proven in 1995 by A. Premet.

Works (selection)

  • Strong approximation for Zariski-dense subgroups of semisimple algebraic groups. Ann. of Math. (2) 120 (1984) no. 2, 271-315.
  • with Matthews, Vaserstein: Congruence properties of Zariski-dense subgroups. I. Proc. London Math. Soc. (3) 48 (1984) no. 3, 514-532.

Web links

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  1. ^ Netty C. Gross: Missing. The tragic case of Boris Weisfeiler, The Jerusalem Report, October 21, 2002, p. 29, pdf
  2. ↑ taz.de: Ray of light after 27 years of blackout in Chile , accessed on October 4, 2017
  3. ↑ weisfeiler.com 2016. A travesty of justice / 2017. Still searching for truth and waiting for justice , accessed on October 4, 2017
  4. ↑ www.somachi-weisfeiler.com SOMACHI's Boris Weisfeiler Campaign , accessed on October 4, 2017
  5. ↑ Alexander Lubotzky, Dan Segal, Subgroup growth, Birkhäuser 2003
  6. ↑ Alexander Lubotzky, The Mathematics of Boris Weisfeiler, Notices AMS, January 2004, p. 32. After that, twenty years later in 2004 it was still the best bound.
  7. ^ V. Kac, B. Weisfeiler, Coadjoint action of a semisimple algebraic group and the center of the enveloping algebra in characteristic p, Indag. Math. 38: 136-151 (1976)
  8. ↑ Premet, irreducible representations of Lie algebras of reductive groups and the Kac-Weis Feiler conjecture, Invent. Math. 121: 79-117 (1995)
personal data
SURNAME Weisfeiler, Boris
BRIEF DESCRIPTION American mathematician
DATE OF BIRTH April 19, 1941
PLACE OF BIRTH Moscow