Homepage Solution manuals David S. Dummit Abstract Algebra Exercise 1.7.15 (Action defined by $g\cdot a = ag^{-1}$)

Exercise 1.7.15 (Action defined by $g\cdot a = ag^{-1}$)

Let G be any group and let A = G . Show that the maps defined by g a = a g 1 for all g , a G do satisfy the axioms of a (left) group action of G on itself.

Answers

Proof. If g , h , a G , then

(i)
g ( h a ) = g ( a h 1 ) = ( a h 1 ) g 1 = a ( h 1 g 1 ) = a ( gh ) 1 = ( gh ) a .
(ii)
e g = g e 1 = g .

The maps defined by g a = a g 1 for all g , a G do satisfy the axioms of a (left) group action of G on itself. □

User profile picture
2025-10-05 10:11
Comments