We construct an invariant of the bi-Lipschitz equivalence of analytic function germs (ℝⁿ,0) → (ℝ,0) that varies continuously in many analytic families. This shows that the bi-Lipschitz equivalence of analytic function germs admits continuous moduli. For a germ f the invariant is given in terms of the leading coefficients of the asymptotic expansions of f along the sets where the size of |x| |grad f(x)| is comparable to the size of |f(x)|.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-bc65-0-5, author = {Jean-Pierre Henry and Adam Parusi\'nski}, title = {Invariants of bi-Lipschitz equivalence of real analytic functions}, journal = {Banach Center Publications}, volume = {65}, year = {2004}, pages = {67-75}, zbl = {1059.32006}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc65-0-5} }
Jean-Pierre Henry; Adam Parusiński. Invariants of bi-Lipschitz equivalence of real analytic functions. Banach Center Publications, Tome 65 (2004) pp. 67-75. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc65-0-5/