We describe all surjective isometries between open subgroups of the groups of invertible elements in unital C*-algebras. As a consequence the two C*-algebras are Jordan *-isomorphic if and only if the groups of invertible elements in those C*-algebras are isometric as metric spaces.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm209-2-1, author = {Osamu Hatori and Keiichi Watanabe}, title = {Isometries between groups of invertible elements in C*-algebras}, journal = {Studia Mathematica}, volume = {209}, year = {2012}, pages = {103-106}, zbl = {1260.46036}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm209-2-1} }
Osamu Hatori; Keiichi Watanabe. Isometries between groups of invertible elements in C*-algebras. Studia Mathematica, Tome 209 (2012) pp. 103-106. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm209-2-1/