This review summarizes more than 100 years of research on spinel compounds, mainly focusing the progress in understanding their magnetic, electronic, and polar properties during last two decades. Many compounds are magnetic insulators or semiconductors; however, a number spinel-type metals exists including superconductors some rare examples d-derived heavy-fermion compounds. In early days, they...

where β is an appropriate positive constant, see [1, 2, 4, 6, 7]. The question of uniqueness of ground states for (1.1) when f(u) has such exponential behavior has not previously been treated; the purpose of this paper is to make a beginning on this problem. Appropriate assumptions on the operator A will be given in the next section. On the other hand, for the nonlinearity f we consider the spe...

We present a study, carried out on 241 participants, which investigates on classical music material the agreement of listeners on perceptual music aspects (related to emotion, tempo, complexity, and instrumentation) and the relationship between listener characteristics and these aspects. For the currently popular task of music emotion recognition, the former question is particularly important w...

One important issue of automated theorem proving is the complexity of the inference rules used in theorem provers. If Krishnamurty's general symmetry rule is to be used, then one should provide some way of computing non trivial symmetries. We show that this problem is NP-complete. But this general rule can be simplified by restricting it to what we call 5symmetries, yielding the well-known symm...

Accurate prediction of the intensity and variability of strong ground motions for future large earthquakes depends on our ability to simulate realistic earthquake source models. While there has been considerable progress in characterizing the complexity of earthquake ruptures, recent devastating earthquakes have exhibited rather unexpected behavior. Moderate-size events occurred with surprising...

We consider the computational complexity of Hamiltonians which are sums of commuting terms acting on plaquettes in a square lattice of qubits, and we show that deciding whether the ground state minimizes the energy of each local term individually is in the complexity class NP. That is, if the ground states has this property, this can be proven using a classical certificate which can be efficien...