I have a question about Fraleigh book of abstract algebra, semidirect products and group action.
Is there any reason for Fraleigh to not include Semidirect products in his book? I have looked into some books and some of them include Semidirect products but not group action, and some other include group action but not semidirect products, some include both. My Abstract Algebra teacher said there is some kind of relation between both of that concepts, but she didn't want to tell me what kind of relation was for some books not to include one of them.