
About the definition of subring - Mathematics Stack Exchange
2018年11月15日 · Then any subring is a #-subring, so the property you've given clearly still holds. As will anything that proves some subset is a subring. The problem is that a #-subring is not …
ring theory - The subring test (subtraction vs. addition closure ...
In abstract algebra, the subring test is a theorem that states that for any ring, a nonempty subset of that ring is a subring if it is closed under multiplication and subtraction. Note that here that …
Prove the following is a subring - Mathematics Stack Exchange
Edit: As pointed out in the comments, you do not need to prove that 0 is the identity since you are proving it is a subring, rather than just proving it is a ring. It should still serve as an example for …
abstract algebra - Relationship between subrings and ideals ...
In the commutative case we identify left and right multiplication and then an ideal is a subring of the ring. However, that is not enough. Since the subring requires closure under multiplication …
The Properties of a Subring - Mathematics Stack Exchange
2018年5月25日 · (R, +, $\ast$) ( $\ast$ := Multiplication) is a ring. A subset S $\subseteq$ R is called subring when (S, +, $\ast$) is a ring. Show the following: S is a subring from R if the …
Subring of PID is also a PID? - Mathematics Stack Exchange
2016年11月6日 · $\begingroup$ Any integral domain is a subring of its field of fractions, which is a PID. Therefore the three classes "subrings of fields", "subrings of PIDs" and "integral domains" …
abstract algebra - How to check a set of ring is a subring ...
2013年8月5日 · You do need to show that it contains an additive inverse for each of its elements. (For example, $\mathbb{N}$ is not a subring of $\mathbb{Z}$ though it is closed under …
abstract algebra - Ring and Subring with different Identities ...
This relies on the existence of a nontrivial idempotent. Since the identity element of any subring has to be idempotent, you can see that the identity of subrings would have to coincide with the …
Show that ideal is a subring - Mathematics Stack Exchange
The factors in such a decomposition are naturally quotients of the original ring, but also correspond to an ideal of that ring (namely the kernel of projecting to the other factor(s)); such …
ring theory - The subring criterion - Mathematics Stack Exchange
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