Dear Guys, Excellent paper, Pawel (clear, pedagogical and deep). Below some (few) suggestions for improvement. Best regards Gérard PS: I didn't put line?, please tell me if the sheet is OK. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Abstract [From this starting point we explore combinatorial]--> [From this starting point, we explore combinatorial] Introduction [where I is multiplicative identity.]--> [where I is the (unique) multiplicative identity.] Heisenberg–Weyl algebra [associative algebra with the unit]--> [associative algebra with unit] sorry, I didn't notice this previously (see Algebras and rings in the following) http://en.wikipedia.org/wiki/Algebra_over_a_field 3.3. Combinatorial realization of the Heisenberg–Weyl algebra [With this equivalence the algebraic structure of H and its]--> [With this equivalence, the algebraic structure of H and its] References [17] [agentle]-->[a gentle]