• Walter Ledermann, Introduction to the Theory of Finite Groups, 1961. The author uses the word complex to mean a subset of a group, a term that appears to have fallen into disuse. I use the term subset or set, and the context implies that there is a group operation that can be applied to its elements.

  • David S. Dummit, Richard M. Foote, Abstract Algebra, 1991.

Ben Lynn 💡