Stiffness of the Edwards-Anderson model in all dimensions.

A comprehensive description in all dimensions is provided for the scaling exponent y of low-energy excitations in the Ising spin glass introduced by Edwards and Anderson. A combination of extensive numerical as well as theoretical results suggest that its lower critical dimension is exactly dl=5/2. Such a result would be an essential feature of any complete theory of low-temperature spin glass order and imposes a constraint that may help to distinguish between theories.