Extra Pure

Question 1

How to spot an abelian group from its Cayley table?

Answer 1

Symmetric about leading diagonal

Question 2

Inverse of
(a b)
(c d)

Answer 2

1/detA
(d -b)
(-c a)

Question 3

What do you have to remember to do when identifying the identity of a group?

Answer 3

Explicitly state “…and ___ is in the group”