  We present empirical evidence, supported by a planet formation model, to show
that the curve $R/R_\oplus = 1.05\,(F/F_\oplus)^{0.11}$ approximates the
location of the so-called photo-evaporation valley. Planets below that curve
are likely to have experienced complete photo-evaporation, and planets just
above it appear to have inflated radii; thus we identify a new population of
inflated super-Earths and mini-Neptunes. Our N-body simulations are set within
an evolving protoplanetary disk and include prescriptions for orbital
migration, gas accretion, and atmospheric loss due to giant impacts. Our
simulated systems broadly match the sizes and periods of super-Earths in the
Kepler catalog. They also reproduce the relative sizes of adjacent planets in
the same system, with the exception of planet pairs that straddle the
photo-evaporation valley. This latter group is populated by planet pairs with
either very large or very small size ratios ($R_{\rm out} / R_{\rm in} \gg 1$
or $R_{\rm out} / R_{\rm in} \ll 1$) and a dearth of size ratios near unity. It
appears that this feature could be reproduced if the planet outside the
photo-evaporation valley (typically the outer planet, but some times not) has
its atmosphere significantly expanded by stellar irradiation. This new
population of planets may be ideal targets for future transit spectroscopy
observations with the upcoming James Webb Space Telescope.
