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It sounds like a limit. xn --> x for n --> :-)

Yeah, that's right. If xn is monotone, then I only have to worry when it is not bounded, right ?

Sorry, don't understand what you mean. Yes, the monotone sequence has a limit. No, it's not necessarily maximal.

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[1 .. ] and x=1:x are maximal ? Can you give me some examples of non maximal ones ?

let x = x+1 in x Or even let x = x in x In both cases, (_|_) is the least fixed point, and is non-maximal.