We introduce the construction of a generalized direct product associated with a graph of groups and prove two sufficient conditions for its existence. These results are applied to obtain some sufficient conditions for an HNN-extension with central associated subgroups to be residually a C-group where C is a root class of groups. In particular, it is proved that an HNN-extension of a solvable group with central associated subgroups is residually solvable.
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Supported by RFBR, project No. 18-31-00187.
Translated from Algebra i Logika, Vol. 58, No. 6, pp. 720-740, November-December, 2019.
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Sokolov, E.V., Tumanova, E.A. Generalized Direct Products of Groups and their Application to the Study of Residuality of Free Constructions of Groups. Algebra Logic 58, 480–493 (2020). https://doi.org/10.1007/s10469-020-09568-x
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DOI: https://doi.org/10.1007/s10469-020-09568-x