I'm working on the book Cyclic Homology by Loday (https://www.math.univ-paris13.fr/~vallette/GdT/Cyclic%20Homology%20-%20Loday.pdf) and in the section 2.2, he constructs the Connes' long exact sequence (Theorem 2.2.1) and he says that the connecting morphism is the morphism B in 2.1.7 but I can't see why. Does someone see why ?
And to be sure that I well understood, in the exact sequence of bicomplexes which gives this long exact sequence, the morphism between CC(A) and CC(A)[2,0] is the natural one who sends $A^{⊗q+1}$ on itself if p is greater than 3 and 0 otherwise ?
Thank you