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Hi everyone!

Given a finite simple group $S$, is it always possible to find two elements $x,y \in S$ with the property that for every $a,b \in S$ we have $\langle x^a,y^b \rangle = S$?

More in general, given a finite almost simple group $X$ with socle $S$, is it possible to find two elements $x,y \in X$ with the property that for every $a,b \in X$ we have $\langle x^a,y^b \rangle \supseteq S$?

I can deal with the alternating case, but I don't know where to look for results about the general case.

Thank you for any contribution.

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Stupid question: With $x^a$ you mean $a^{-1} x a$ ? – mnr Oct 31 '11 at 10:41
Hei Arno :) yes, I mean that. – Martino Garonzi Oct 31 '11 at 11:28
up vote 5 down vote accepted

This property is known as "being invariably generated by $x$ and $y$" in the literature (though it has not been so extensively studied). For a nonabelian finite simple group, Kantor, Lubotzky and Shalev have shown that, indeed, such $x$ and $y$ exist. (This is Theorem 1.3 in , which contains a lot of interesting material on similar questions).

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Great! Thank you ! – Martino Garonzi Oct 31 '11 at 15:28

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