On the Chang's group of BL-algebras
  For an arbitrary BL-algebra L, we construct an associated lattice Abelian group that coincides with Chang's group when the BL-algebra is an MV-algebra. We prove that the Chang's group of the MV-center of any BL- algebra L is a direct summand in the above group. We also compute examples of this group. 
Jean B. Nganou, Celestin Lele
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