Let N be a quasivariety of torsion-free nilpotent groups of class at most two. It is proved that the set of subquasivarieties in N, which have no independent basis of quasiidentities and are generated by a finitely generated group, is infinite. It is stated that there exists an infinite set of quasivarieties M in N which are generated by a finitely generated group and are such that for every quasivariety K(M ⊈ K ⊆ N), an interval [M, K] has the power of the continuum in the quasivariety lattice.

中文翻译：

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无扭幂零群拟方差的独立公理化

设N是至多为两个类的无扭幂零群的拟变异。证明了N 中没有独立的拟恒等基并由有限生成群生成的子拟变量集是无限的。据说，存在一个无限集合的quasivarieties中号中Ñ其通过有限生成组产生的，并且使得对于每quasivariety ķ（中号 ⊈  ķ  ⊆  Ñ），间隔[ M，K ]具有的功率准变异格中的连续体。