8 Oct
2009
8 Oct
'09
2:39 p.m.
The Diffie-Hellman operation a # b = exp(ln(a) ln(b)).
This reminds me of Marc LeBrun's map (a,b) -> a_b, where if a = Sum c_i 10^i (0 <= c_i <= 9) is the decimal expansion of a, then a_b = Sum c_i b^i, which we studied in arXiv:math.NT/0611293. It satisfies 10^( [ln a] ln b ) <= a_b <= 10^( ln a ln b ) and has a number of other nice properties! Neil