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I'm looking for an example of a ring $R$ (necessarily nonunital) which is simple (in the sense that $R \cdot R \neq 0$ and $R$ has no proper, nonzero 2-sided ideals) and also radical (in the sense that the Jacobson radical $J(R)$ is all of $R$). My only thought so far has been that it suffices to find a simple ring in which all elements are nilpotent. Thanks.

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up vote 3 down vote accepted

The first example of a simple radical ring was constructed in 1961 by E. Sasiada, see:

  • E. Sasiada, Solution of the problem of existence of a simple radical ring, Bull. Acad. Polon. Sci. Ser. Sci. Math. Astr. Phys. 9 (1961) 257

  • E. Sasiada and P. M. Cohn, An example of a simple radical ring, J. Algebra 5 (1967) 373-377.

The problem of the existence of a simple nil ring remained open until 2002, when it was solved by A. Smoktunowicz, see:

  • A. Smoktunowicz, A simple nil ring exists, Communications in Algebra 30 (2002), no.1, 27-59.

I did some googling and found the following book in which Sasiada's construction is presented in the form of an exercise.

Added: I did some further googling and found the following article which might also be of interest.

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Thanks this is useful – Mike F Apr 25 '12 at 21:10

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