  We present numerical evidence showing that any three-dimensional subspace of
C^3 \otimes C^n has an orthonormal basis which can be reliably distinguished
using one-way LOCC, where a measurement is made first on the 3-dimensional part
and the result used to select an optimal measurement on the n-dimensional part.
This conjecture has implications for the LOCC-assisted capacity of certain
quantum channels, where coordinated measurements are made on the system and
environment. By measuring first in the environment, the conjecture would imply
that the environment-assisted classical capacity of any rank three channel is
at least log 3. Similarly by measuring first on the system side, the conjecture
would imply that the environment-assisting classical capacity of any qutrit
channel is log 3. We also show that one-way LOCC is not symmetric, by providing
an example of a qutrit channel whose environment-assisted classical capacity is
less than log 3.
