Is Every Ideal Being Prime Indicative of a Commutative Ring Being a Field?

In summary, the problem states that if every ideal in a commutative ring with unity is prime, then the ring must be a field. The suggested approach is to show that a ring is a field if and only if it has no nontrivial ideals, and then use this to prove that the ring in question is an integral domain. By considering the ideal that consists of only the zero element, it can be shown that the ring must be an integral domain. To complete the proof, it must be shown that every non-zero element is a unit. This can be done by considering the ideal generated by the square of a non-zero element.
  • #1
fireisland27
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Homework Statement



Given a commutative ring with unity, show that if every ideal is prime than the ring is a field.

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The Attempt at a Solution



I think that I can show that a ring is a field iff it has no nontrivial ideals. So I guess I need to show that if a ring has only prime ideals than these ideals must be trivial. I'm not sure how to do this though.
 
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  • #2
Can you show that the ring must be an integral domain? (Hint: Consider the ideal that consists just of the zero element.) Next show that every non-zero element is a unit to complete the proof. (Hint: Let r be a non-zero element. Consider the ideal generated by [itex]r^2[/itex].)

Petek
 

FAQ: Is Every Ideal Being Prime Indicative of a Commutative Ring Being a Field?

What is a prime ideal in ring theory?

A prime ideal in ring theory is a special type of ideal in a commutative ring that shares many properties with prime numbers in the integers. It is an ideal that cannot be factored into smaller ideals, and its quotient ring is an integral domain.

How is a prime ideal different from a maximal ideal?

A maximal ideal is an ideal that is not a subset of any other proper ideal, while a prime ideal is an ideal that is not a subset of any other proper ideal except for the zero ideal. In other words, a maximal ideal is "bigger" than a prime ideal.

What is the significance of prime ideals in ring theory?

Prime ideals play a crucial role in the structure and properties of commutative rings. They are used to define prime elements and irreducible elements in a ring, and they are essential in proving the fundamental theorem of arithmetic. Prime ideals also have applications in algebraic geometry and number theory.

Can a ring have more than one prime ideal?

Yes, a ring can have multiple prime ideals. For example, the ring Z[x] (the set of polynomials with integer coefficients) has an infinite number of prime ideals, including the ideal generated by x, the ideal generated by 2 and x, and the ideal generated by 3 and x.

How are prime ideals related to prime numbers?

In a ring of integers, prime ideals correspond to prime numbers. This is because a prime number p generates a prime ideal in the ring Z, and this ideal then generates a prime ideal in any ring that contains Z. This connection allows us to extend the concept of prime numbers to other rings through prime ideals.

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