where the final $N(E)$ resembles the initial one. We interpret this result as another manifestation of a less effective phase-space reorganization in MOND than in Newtonian collapses.

Comparison with the observed scaling relations of elliptical galaxies {#secsca}
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It is not surprising that galaxy scaling relations represent an even stronger test for MOND than for Newtonian gravity, due to the absence of dark matter and the existence of the critical acceleration ${a_0}$ with a universal value in the former theory (e.g., see Milgrom 1984; Sanders 2000). For example, when interpreting the FP tilt in Newtonian gravity one can invoke a systematic and fine-tuned increase of the galaxy dark-to-luminous mass ratio with luminosity (e.g., Bender, Burstein & Faber 1992; Renzini & Ciotti 1993; Ciotti, Lanzoni & Renzini 1996), while in MOND the tilt should be related to the characteristic acceleration ${a_0}$. Note, however, that in MOND as well as in Newtonian gravity other important physical properties may help to explain the FP tilt, such as a systematic increase of radial orbital anisotropy with mass or a systematic structural weak homology (Bertin et al. 2002). Due to the relevance of the subject, we attempt here to derive some preliminary hints. In particular, 