Question

example of commutative ring without unity element ​

Answer 1

Answer:

1 Z is a commutative ring with unity. 2 E = {2k | k ∈ Z} is a commutative ring without unity. 3 Mn(R) is a non-commutative ring with unity. 4 Mn(E) is a non-commutative ring without unity

Answer 2

Answer:

1 Z is a commutative ring with unity. 2 E = {2k | k ∈ Z} is a commutative ring without unity. 3 Mn(R) is a non-commutative ring with unity. 4 Mn(E) is a non-commutative ring without unity