mm-1549 sum_{p <= n} 1/p = log log n + C + O(1/log n) where C = gamma + sum_p [log(1 - 1/p) + 1/p]. IIRC this is due to Mertens and is in Hardy and Wright. You want to go up to p(n) which is ~ n log n by PNT, so you'd replace log log n by log(log n + log log n) which is still as-near-as-dammit log log n. -- Robin Chapman, www.maths.ex.ac.uk/~rjc/rjc.html Elegance is an algorithm Iain M. Banks, _The Algebraist_ Hmm I guess thats |2t|<2 .Sorry,again Stuart M Newberger http://www.cs.uu.nl/wais/html/na-dir/sci-math-faq/axiomchoice.html Then the FAQ is mistaken? And these statements depend on AC (i.e., they cannot be proved in ZF without AC): * The union of countably many countable sets is countable. * Every infinite set has a denumerable subset. * The Loewenheim-Skolem Theorem: Any first-order theory which has a model has a denumerable model. * The Baire Category Theorem: The reals are not the union of countably many nowhere dense sets (i.e., the reals are not meager). * The Ultrafilter Theorem: Every Boolean algebra has an ultrafilter on it. No, the statements cited are not arithmetical. No, from G.9adel's work on the constructible hierarchy. The full story is told by Platek in a paper in the Journal of Symbolic Logic, vol 34 no 2 1969. In the particular case of AC or CH, there is no significant increase in the length of proofs. But we know that extending a theory T by a statement A undecidable in T will shorten the proofs of some statements to any extent, in the sense that for any recursive function f there is a statement B such that f(p)