Suppose H0 artinian, and let M be a free graded H-module generated by s homogeneous, linearly independent elements, of respective degrees δ1,...,δs. Then M is isomorphic to H(−δ1)⊕⋯⊕H(−δs). By remarks 2 and 3 and example 1, we therefore have
PM=long(H0)(i=1∑sTδi)(1−T)−r,
QM=long(H0)(i=1∑sTδi),
cM=s.long(H0).
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.