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Jun26-05, 01:17 AM
why would you want ax=xa anyway? that is not the condition of normality of a subgroup. H is normal if for gx in gH there is an element y of H such that yg=gx, there is no requirement that x=y.
I hadn't realised that.
did you redo the proof of the last problem to be a one line proof NOT by contradiction? it would be helpful to your understanding to do it.
May I have a hint?