A variant of the accelerating cosmology reconstruction program is developed
for f(R) gravity and for a modified Yang-Mills/Maxwell theory. Reconstruction
schemes in terms of e-foldings and by using an auxiliary scalar field are
developed and carefully compared, for the case of f(R) gravity. An example of
a model with a transient phantom behavior without real matter is explicitly
discussed in both schemes. Further, the two reconstruction schemes are applied
to the more physically interesting case of a Yang-Mills/Maxwell theory, again
with explicit examples. Detailed comparison of the two schemes of
reconstruction is presented also for this theory. It seems to support, as well,
physical non-equivalence of the two frames.Comment: 16 pages, no figures, version to appear in Phys Rev