Abstract We establish explicit expressions for the ‐theory classes of higher Kazhdan projections for amalgamated product groups . Our approach follows the methodology developed by Pooya and Wang for free product groups , and naturally generalizes their results on free products. As an application of the ‐class expressions, we obtain nonvanishing results for delocalized ‐Betti numbers of .
Baiying Ren (Sun,) studied this question.