A ferromagnet with a glass transition

We introduce a finite-connectivity ferromagnetic model with a three-spin in teraction which has a crystalline ( ferromagnetic) phase as well as a glass phase. The model is not frustrated, it has a ferromagnetic equilibrium pha se at low temperature which is not reached dynamically in a quench from the high-temperature phase. Instead it shows a glass transition which can be s tudied in detail by a one-step replica-symmetry broken calculation. This sp in model exhibits the main properties of the structural glass transition at a solvable mean-field level.