The transformation of the interval studied, leaves invariant a Canter set o
n which subsists a neutral fixed point. The non-expanding dynamical system
defined is topologically conjugate to the full-shift on a two-symbol alphab
et. We first prove that the ergodic measure are exact dimensional. Then, th
e multifractal analysis of the g-measures is obtained by using the underlyi
ng thermodynamic formalism. Finally, we prove an extension of the so-called
Bowen formula which gives, the Hausdorff dimension of the Cantor set studi
ed. (C) 2000 Academie des sciences/Editions scientifiques et medicales Else
vier SAS.