Question

In: Advanced Math

An element a in a ring R is called nilpotent if there exists an n such...

An element a in a ring R is called nilpotent if there exists an n such that an = 0.

(a) Find a non-zero nilpotent element in M2(Z).

(b) Let R be a ring and assume a, b ∈ R have at = 0 and bm = 0 for some positive integers t and m. Find an n so that (a + b)n = 0. (You just need to find any n that will work, not the smallest!)

(c) Show that the set of nilpotent elements in a commutative ring R forms a subring of R.

(d) Does this subring from the previous question contain a unity?

(e) Are the Gaussian integers from an earlier question an integral domain? Explain your answer.

Solutions

Expert Solution


Related Solutions

Let R be a ring and n ∈ N. Let S = Mn(R) be the ring...
Let R be a ring and n ∈ N. Let S = Mn(R) be the ring of n × n matrices with entries in R. a) i) Let T be the subset of S consisting of the n × n diagonal matrices with entries in R (so that T consists of the matrices in S whose entries off the leading diagonal are zero). Show that T is a subring of S. We denote the ring T by Dn(R). ii). Show...
Describe the ring obtained from the product ring R×R by inverting the element (2,0). and we...
Describe the ring obtained from the product ring R×R by inverting the element (2,0). and we already know that the ring R x R is isomorphic to R[x]/(x^2-1)
An element e of a ring is called an idempotent if e^2 = e. Find a...
An element e of a ring is called an idempotent if e^2 = e. Find a nontrivial idempotent e in the ring Z143.
Let R be a ring and f : M −→ N a morphism of left R-modules. Show that:
Let R be a ring and f : M −→ N a morphism of left R-modules. Show that: c) K := {m ∈ M | f(m) = 0} satisfies the Universal Property of Kernels. d) N/f(M) satisfies the Universal Property of Cokernels. Q2. Show that ZQ :a) contains no minimal Z-submodule
Let R be a ring and f : M −→ N a morphism of left R-modules. Show that:
Let R be a ring and f : M −→ N a morphism of left R-modules. Show that: c) K := {m ∈ M | f(m) = 0} satisfies the Universal Property of Kernels. d) N/f(M) satisfies the Universal Property of Cokernels.  
Let F be a field and R = Mn(F) the ring of n×n matrices with entires...
Let F be a field and R = Mn(F) the ring of n×n matrices with entires in F. Prove that R has no two sided ideals except (0) and (1).
c) Let R be any ring and let ??(?) be the set of all n by...
c) Let R be any ring and let ??(?) be the set of all n by n matrices. Show that ??(?) is a ring with identity under standard rules for adding and multiplying matrices. Under what conditions is ??(?) commutative?
let R be a ring; X a non-empty set and (F(X, R), +, *) the ring...
let R be a ring; X a non-empty set and (F(X, R), +, *) the ring of the functions from X to R. Show directly the associativity of the multiplication of F(X, R). Assume that R is unital and commutative. show that F(X, R) is also unital and commutative.
Let R be a ring with at least two elements. Prove that M2×2(R)is always a ring...
Let R be a ring with at least two elements. Prove that M2×2(R)is always a ring (with addition and multiplication of matrices defined as usual).
For an arbitrary ring R, prove that a) If I is an ideal of R, then...
For an arbitrary ring R, prove that a) If I is an ideal of R, then I[ x] forms an ideal of the polynomial ring R[ x]. b) If R and R' are isomorphic rings, then R[ x] is isomorphic to R' [ x ].
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT