Given a sentence-
Professor's father's son is talking to Professor's son's father.
which is a correct sentence. You have to prove it.
where professor is the same person and he is not talking to himself.

Question

Given a sentence-
Professor's father's son is talking to Professor's son's father.
which is a correct sentence. You have to prove it.
where professor is the same person and he is not talking to himself.

anonymous · Answer

P's father's son is P's brother. 
P's son's father is P.

P's is talking to his brother.

anonymous · Answer

HOWEVER, allow me to throw in an exception:

Taken from the dictionary, a professor is "a faculty member of the highest academic rank at an institution of higher education".

Because it is a profession and therefore not limited to one particular gender (at least not here in the Western world as far as I'm aware) the problem takes a slight turn when you consider that the professor might be a woman.

P's father's son is still her brother. However :

P's son's father is no longer P but rather P's husband. 

Ergo, her brother is talking to her husband and P's in the kitchen.