  We consider an irreversible autocatalytic conversion reaction A+B -> 2A under
subdiffusion described by continuous time random walks. The reactants'
transformations take place independently on their motion and are described by
constant rates. The analog of this reaction in the case of normal diffusion is
described by the Fisher-Kolmogorov-Petrovskii-Piskunov (FKPP) equation leading
to the existence of a nonzero minimal front propagation velocity which is
really attained by the front in its stable motion. We show that for
subdiffusion this minimal propagation velocity is zero, which suggests
propagation failure.
