Defining the local part of a hidden variable model: a comment

Understand

In [Physical Review Letters 101, 050403 (2008)], we showed that quantum theory cannot be explained by a hidden variable model with a non-trivial local part.

• The purpose of this comment is to clarify our notion of local part, which seems to have caused some confusion in the recent literature.
• This notion is based on Bell's and demands that local hidden variables are physical, the idea being that, if discovered, they would not contradict basic physical principles.
• We explain why the recent supposed "counterexamples" that have appeared are not counterexamples to our theorem--in fact they are based on a definition of local hidden variables which would allow signalling and is therefore not physical.