In this note we determine explicit formulas for the relative commutator of groups with respect to the subvarieties of $n$-nilpotent groups and of $n$-solvable groups. In particular these formulas give a characterization of the extensions of groups that are central relatively to these subvarieties.
@article{108014, author = {Tomas Everaert and Marino Gran}, title = {Relative commutator associated with varieties of $n$-nilpotent and of $n$-solvable groups}, journal = {Archivum Mathematicum}, volume = {042}, year = {2006}, pages = {387-396}, zbl = {1152.20030}, mrnumber = {2283019}, language = {en}, url = {http://dml.mathdoc.fr/item/108014} }
Everaert, Tomas; Gran, Marino. Relative commutator associated with varieties of $n$-nilpotent and of $n$-solvable groups. Archivum Mathematicum, Tome 042 (2006) pp. 387-396. http://gdmltest.u-ga.fr/item/108014/
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