21. The 2D Ising model was the first model to exhibit a continuous phase transition at a positive temperature. 22. It may then have applications to the study of the duality to the 3-dimensional Ising model . 23. The one-dimensional Ising model has no phase transition and was solved by himself in his 1924 thesis. 24. The Ising model undergoes a phase transition between an ordered and a disordered phase in 2 dimensions or more. 25. The behavior of an Ising model on a fully connected graph may be completely understood by mean field theory. 26. That the theorem does not apply to discrete symmetries can be seen in the two-dimensional Ising model . 27. User : YellowMonkey by comparison did an excellent job on largely the same material in square lattice Ising model . 28. The interactions of neurons in a small network can be often reduced to simple models such as the Ising model . 29. The Ising model was invented by the physicist, who gave it as a problem to his student Ernst Ising. 30. But many aspects are, such as obtaining the exact expression for the free energy for the 2d Ising model .
