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Timeline for Schreier's index formula

Current License: CC BY-SA 3.0

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Apr 22, 2014 at 22:44 vote accept Pablo
Apr 17, 2014 at 13:05 comment added Pablo Suppose $H$ is a given subgroup containing the k-th derived subgroup of $F$. Must there be a finite index subgroup above $H$ violating Schreier's formula? I'm interested in this in the profinite case too.
Apr 16, 2014 at 10:46 vote accept Pablo
Apr 16, 2014 at 10:46
Apr 16, 2014 at 10:46 vote accept Pablo
Apr 16, 2014 at 10:46
Apr 15, 2014 at 13:02 comment added Benjamin Steinberg Free pro-solvable groups and free pro-p groups satisfy Schreier's formula.
Apr 15, 2014 at 7:27 comment added Pablo Ok, I think I've got you. What if instead F is the free profinite group on a finite number of generators? In this case the aforementioned intersection is not trivial.
Apr 14, 2014 at 20:17 comment added Benjamin Steinberg The intersection of all the terms of the derived series is trivial because the free group is residually a finite p-group and hence residually solvable. So you do get a free group and there is no contradiction.
Apr 14, 2014 at 19:59 comment added Pablo If you take the quotient of F by the intersection of all the terms in its derived series you get a finitely generated residually finite group, which is not free but satisfies Schreier's index formula. Does this contradict your claim?
Apr 14, 2014 at 16:43 history answered Benjamin Steinberg CC BY-SA 3.0