cores of most massive stars should be slowly spinning. However, there may be exceptions of rapidly spinning cores at just about the right occurrence rate to explain hypernovae and long gamma-ray bursts.

Besides the neutrino mechanism and the magnetorotational mechanism, a number of other explosion mechanisms have been proposed. I direct the interested reader to the more extensive review by [@janka:12a].

A Multi-Scale, Multi-Physics, Multi-Dimensional Computational Challenge
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The core-collapse supernova problem is highly complex, inherently non-linear, and involves many branches of (astro)physics. Only limited progress can be made with analytic or perturbative methods. Computational simulation is a powerful means for gaining theoretical insight and for making predictions that could be tested with astronomical observations of neutrinos, gravitational waves, and electromagnetic radiation.

Core-collapse supernova simulations are time evolution simulations – starting from initial conditions, the matter, radiation, and gravitational fields are evolved in time. In the case of time-explicit evolution, the numerical timestep is limited by causality, controlled by the speed of sound in Newtonian simulations, and the speed of light in general-relativistic simulations. Because of this, an increase in the spatial resolution by a factor of two corresponds to a decrease in the time step by a factor of 