- #36
matt grime
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I didn't say there wasn't a connection (though what you mean by that is unclear) but that the addition of two real numbers is independent of the choice of decimal expansion, should it have two. The simple proof of this fact follows from the definition of the real numbes as the completion of the rationals. Go and get a basic analysis book. Just because you do not know it, Organic, does not mean it is not true or known by other better informed people. Proof: let x_n and y_n be two equivalent Cauchy sequences. This means x_n-y_n converges to zero. Let w_n and v_n ba any other pair of equivanlent cauchy sequences.
then the element of R that [x_n-w_n] coresponds to is the same as the class (real number) [y_n-v_n]
proof: we are to show x_n-w_n-y_n+v_n converges to zero, but that is trivially true since |x_n-w_n_y_n+v_n| < |x_n-y_n| +|w_n-v_n| and both those terms can, be made arbitrarily small by hypothesis,a nd we have proved subtraction of two real numbers is indpendent of the Cauchy sequences we pick to represent them. OK?
then the element of R that [x_n-w_n] coresponds to is the same as the class (real number) [y_n-v_n]
proof: we are to show x_n-w_n-y_n+v_n converges to zero, but that is trivially true since |x_n-w_n_y_n+v_n| < |x_n-y_n| +|w_n-v_n| and both those terms can, be made arbitrarily small by hypothesis,a nd we have proved subtraction of two real numbers is indpendent of the Cauchy sequences we pick to represent them. OK?