EINSTEIN, ALBERT

Autograph letter signed ("A.E."), in German, to the mathematician Ernst Gabor Straus, WITH THREE EQUATIONS, APPARENTLY RELATING TO EINSTEIN'S WORK ON SPHERICALLY SYMMETRIC SOLUTIONS OF HIS UNIFIED THEORY *[spring 1945?]*

observing that Straus must have made a mistake in his central symmetry calculations, illustrating his point by means of three equations, noting with typical modesty that he himself is very prone to errors of calculation and that he is not convinced that his findings are correct, explaining that he is informing him straight away so that he doesn't labour away on what might prove to be incorrect foundations

...Ich habe die Sache mit dem zentralsymmetrischen s durchgerechnet, und es scheint mir, dass Sie einen Rechenfehler gemacht haben müssen...Ich neige sehr zu Rechenfehlern und bin nicht überzeugt, dass dieser Befund richtig ist. Ich teile es Ihnen aber doch sofort mit, dass Sie nicht auf eine eventuel[l] unrichtige Grundlage Mühe verwenden und in die Irre gehen. Erst wenn wir sicher sind, dass in der zentralsymmetrischen Lösung willkürliche Funktionen bleiben, müssen wir die Grundlage abzuändern versuchen...

1 page, 4to (27.7 x 21.3cm), paper watermarked "Whiting Mutual Bond", no place, Friday, [spring 1945?]

A WORKING MANUSCRIPT FROM EINSTEIN'S LAST DECADE.

The major part of Einstein's activities in the period before his death in 1955 concerned a proposed and ultimately unsuccessful 'Unified' theory, one which went beyond his General Relativity and attempted to incorporate the electromagnetic field as described by Maxwell's equations. Although it is possible that Einstein's letter refers to his cosmological work concerning a spherically symmetric (or centrally symmetric) solution of his equations representing a spherically symmetric star inside a spherically symmetric cavity surrounded by a spherically symmetric expanding universe, it would seem in fact that it concerns attempts by Einstein and Straus to find everywhere regular, spherically symmetric solutions of Einstein's newly formulated Unified theory of Gravity and Electromagnetism representing elementary particles.

Einstein's correspondent was the German-American mathematician Ernst Gabor Straus (1922-1948) who, for four years, between 1944 and 1948, was Einstein's assistant at the Institute for Advanced Study, Princeton, afterwards moving to UCLA where he remained for the rest of his life. In 1948 Straus was awarded a doctorate at Columbia University on the subject of Einstein's unified field theory. His publication 'Some Results in Einstein's Unified Field Theory', of 1949, was based on his thesis.

We are pleased to acknowledge the kind assistance of Professor Gary Gibbons in our cataloguing of this lot. Please see the bibliography for this lot on sothebys.com.

**LITERATURE:**

A. Einstein and W. Pauli, 'On the Non-Existence of Regular Stationary Solutions of Relativistic Field Equations', *Annals of Mathematics*, series 2, vol.44 (1943), pp.131-137; A. Einstein, 'A Generalization of the Relativistic Theory of Gravitation', *Annals of Mathematics*, second series, vol.46, no. 4 (October 1945 [received 19 June 1945]), pp. 578-584; A. Einstein and E.G. Straus, 'A Generalization of the Relativistic Theory of Gravitation, II', *Annals of Mathematics*, series 2, vol.47, no.4 (October 1946 [received 24 January 1946]), pp.731-741; A. Einstein and E.G. Straus, 'The Influence of the Expansion of Space on the Gravitation Fields surrounding the Individual Stars', *Reviews of Modern Physics*, 17 (April-July 1945), pp.120-124; A. Einstein and E.G. Straus, 'Corrections and Additional Remarks to our Paper: The Influence of the Expansion of Space on the Gravitational Fields Surrounding the Individual Stars', *Reviews of Modern Physics*, 18 (January 1946), pp.148-149; A. Einstein, 'A Generalized Theory of Gravitation', *Reviews of Modern Physics*, 20 (July 1948), pp.35-39; E.G. Straus, 'Some Results in Einstein's Unified Field Theory', *Reviews of Modern Physics*, 21 (July 1949), pp.414-420

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