Rings Definition and 437 Threads

  1. L

    What Are the Ideals and Units in These Factor Rings?

    The first question is to find the ideals of R[x]/<x^2 - x>. I can see that the elements of the factor ring are of the form p(x) + <x^2 - x>, where p(x) is in R[x], which can be simplified to q(x)(x^2 - x) + r(x) + <x^2 - x> = r(x) + <x^2 - x>, where r(x) is of degree 1 or 0. Now I'm pretty much...
  2. S

    Can vortex rings travel at supersonic speeds?

    After a bit of searching of scholarly text and investigations I have found myself unable to find the next piece of information. Can there exist a vortex ring which travels at supersonic speeds? Not as in the airflow within the vortex ring, there was a paper I was able to acquire about that...
  3. T

    Mechanics of smooth rings and string

    Homework Statement A smooth ring with a mass m is threaded through a light inextensible string .The ends of the string are tied to two fixed points A and B on a horizontal ceiling so that the ring is suspended and can slide freely on the string.A hotizontal force acts on the ring in a...
  4. N

    Why is the center point black in Newton's Rings?

    So we know Newton's rings. I have two concrete questions: 1) Why is the center point black? I quote from my book: "Because there is no path difference and the total phase change is due only to the 180° phase change upon reflection, the contact point is dark." I'm not quite sure what they...
  5. K

    First isomorphism theorem for rings

    Homework Statement I have to show that \sum ai xi -> (a0 \sum ai) is a ring homomorphism from C[x] to C x C I then have to use the first isomorphism theorem to show that there is an isomorphism from C[x]/ (x(x-1)) to C x C where (x(x-1)) is the principal ideal (p) generated by the element...
  6. G

    Indoor Tree Growth: Tree Rings & Leaf Shedding

    Sorry if this is the wrong section (already posted it in the biology forum and got no response) but this question comes from a convo I had with some friends the other night.. Say you were able to grow a full size tree indoors (assuming you had the space, nessesary lighting, soil, etc..) and...
  7. B

    Understanding Newton's Rings and Coherence in Interference Patterns

    I'm trying to understand Newton's rings. So we have a plano-convex lens supported in a plane (please, see image here http://scienceworld.wolfram.com/physics/NewtonsRings.html). The incident light is divided into the light that is reflected at the convex surface and the light that is reflected at...
  8. G

    Can indoor-grown trees form tree rings without experiencing a winter season?

    Sorry if this is the wrong section but this question comes from a convo I had with some friends the other night.. Say you were able to grow a full size tree indoors (assuming you had the space, nessesary lighting, soil, etc..) and kept it under 18 hours of light and 6 hours of dark...
  9. B

    Is a Direct Sum of Rings Composed of Elements from Each Original Ring?

    This may be a dumb question, but I just want to make sure I understand this correctly. For R_{1}, R_{2}, ..., R_{n} R_{1} \oplus R_{2} \oplus, ..., R_{n}=(a_{1},a_{2},...,a_{n})|a_{i} \in R_{i} does this mean that a ring which is a direct sum of other rings is composed of specific elements...
  10. W

    Why there is not ring homomorphism between these rings?

    Homework Statement Proof that there is no ring homomorphism between M2(R) [2x2 matrices with real elements] and R2 (normal 2-dimensional real plane). Homework Equations -- The Attempt at a Solution I have tried to proof this problem with properties of ring homomorphism (or finding...
  11. F

    Doing a problem on rings from Dummit & Foote I think I'm mis-reading it

    Homework Statement Decide which of the following are subrings of the ring of all functions from the closed interval [0,1] to R (the reals) a) The set of all functions f(x) such that f(q) = 0 for all q in Q (the rationals) & q in [0, 1] b) The set of all polynomial functions c) The set...
  12. F

    Why do Newton Rings Form in Circular Patterns?

    why are Newton rings observed in a circuler pattern?
  13. J

    Isomorphic Rings: \mathbb{F}_5[x]/(x^2+2) and \mathbb{F}_5[x]/(x^2+3)

    Homework Statement Hi guys, I'm trying to show that \mathbb{F}_5[x]/(x^2+2) and \mathbb{F}_5[x]/(x^2+3) are isomorphic as rings. The Attempt at a Solution As I understand it, I have to find the homomorphism \phi:R\to S which is linear and that \phi(1)=1. I'm just struggling to find...
  14. J

    Solving Isomorphic Rings: \mathbb{F}_5[x]/(x^2+2) & \mathbb{F}_5[x]/(x^2+3)

    Hi guys, I'm trying to show that \mathbb{F}_5[x]/(x^2+2) and \mathbb{F}_5[x]/(x^2+3) are isomorphic as rings. As I understand it, I have to find the homomorphism \phi:R\to S which is linear and that \phi(1)=1. I'm just struggling to find what I need to send x to in order to get this work.
  15. E

    Good book on linear algebra over rings (i.e. modules)

    Can anyone recommend a book that covers linear algebra through the perspective of modules? I am basically trying to find something that would highlight all the differences between modules and vector spaces. Lam has written the book Lectures on Rings and Modules, which is good, but doesn't...
  16. L

    E field at a point between two rings

    1. Two 10-cm-diameter charged rings face each other, 19.0 cm apart. Both rings are charged to + 50.0 nC. What is the electric field strength at the center of the left ring? 2. E = q/(4*pi*epsilon*r2 3. Ok, the E field from the left ring is zero at this point due to...
  17. Z

    Prove R[x]/(x^2)+a Isomorphic to Complex Numbers If a>0, RxR If a<0

    Hello could someone help me out with this question Show that R[x]/(x^2)+a isomorphic to the complex numbers if a>0 and RxR if a<0. Here is an attempt! for mulitplication in R[x]/(x^2)+a Elements of \mathbb{R}[X]/(X^2+a) are cosets: f(X) + (X^2+a). By the polynomial division...
  18. I

    Quotient Rings and Homomorphisms

    Homework Statement Let R and S be rings. Show that \pi:RxS->R given by \pi(r,s)=r is a surjective homomorphism whose kernel is isomorphic to S. Homework Equations The Attempt at a Solution To show that \pi is a homomorphism map, I need to show that it's closed under addition and...
  19. L

    Electric Field Between Two Charged Rings: Problem Solved

    1. Two 10-cm-diameter charged rings face each other, 19.0 cm apart. Both rings are charged to + 50.0 nC. What is the electric field strength: At the midpoint between the two rings? At the center of the left ring? 2. E = q/4pi*ep_o*r^2 3. The online problem says this is from a...
  20. L

    Abstract algebra: Rings and Ideals

    Homework Statement The problem is to show that a subset A of a ring S is an ideal where A has certain properties. S is a ring described as a cartisian product of two other rings (i.e., S=(RxZ,+,*)). I have already proved that A is a subring of S and proved one direction of the definition of an...
  21. R

    Do Left and Right Semisimplicity Coincide in Non-Unital Rings?

    I am interested in semisimple rings and semisimple modules which are not unital. There are two concepts of ring semisimplicity: left semisimplicity and right semisimplicity. A ring is called semisimple on the left if it is presented as a sum of its simple left ideals. A ring is called semisimple...
  22. D

    Exploring the Intuition Behind Rings in Abstract Algebra

    Ok so I am not a math major and i haven't taken an abstract algebra class but i am curoius about the subject. I have been watching video lectures at UCCS at http://cmes.uccs.edu/Fall2007/Math414/archive.php?type=valid and the proffessor talks about groups and rings. In the introduction the...
  23. A

    Direct Sum vs Direct Product of Rings: Irish & Rosen

    What's the difference (if any) between a direct sum and a direct product of rings? For example, in Ireland and Rosen's number theory text, they mention that, in the context of rings, the Chinese Remainder Theorem implies that \mathbb{Z}/(m_1 \cdots...
  24. M

    Let's Talk Bearing Spring Rings

    OK, in bearings (particularly roller) often times there will be a "spring ring" around it. The ring acts to soften the support structure for the bearing. Ring is typically a thin ring with "pads" on both the inside and outside. They are staggered such to put the thin ring into bending when load...
  25. mugaliens

    Theorem of quantum-mechanical version of Borromean rings finally proven

    http://news.yahoo.com/s/livescience/20091216/sc_livescience/strangephysicaltheoryprovedafternearly40years" . "Efimov theorized an analog to the rings using particles: Three particles (such as atoms or protons or even quarks) could be bound together in a stable state, even though any two of...
  26. S

    Curved glass and Newton's Rings

    Homework Statement A piece of curved glass has a radius of r=10m and is used to form Newton's Rings. Not counting the dark spot in the center of the pattern, there are one hundred dark fringes the last one on the outer edge of the curved piece of glass. The light being used has a wavelength...
  27. M

    Understanding A as a Factor Ring of Q[x] and Proving its Field Properties

    Homework Statement : Hey guys, I'm a new user so my semantics might be difficult to read... Let A={a+b(square root(2)) ; a,b in Q} (i)Describe A as a factor ring of Q[x] ( The polynomial Ring) (ii) Show A is a field The Attempt at a Solution (i) Let x be in C (the...
  28. S

    Why do planets of our solar system orbit in rings not spheres?

    I was looking at this link: http://en.wikipedia.org/wiki/File:Universe_Reference_Map_%28Location%29_001.jpeg" and wondered to myself why the asteroid belt just outside of Mars is a ring...as opposed to a sphere. Then I thought, why do all the planets seem to orbit the sun on a similar plane...
  29. C

    Is <S> equal to the intersection of all ideals in R that contain S?

    Homework Statement The following are equivalent for S\subseteqR, S\neq\oslash, and R is a commutative ring with unity(multiplicative identity): 1. <S> is the ideal generated by S. 2. <S> = \bigcap(I Ideal in R, S\subseteqI) = J 3. <S> = {\sumrisi: is any integer from 1 to n, ri\inR \foralli...
  30. M

    Concentric rings and net electric fields

    Homework Statement The figure below shows two concentric rings, of radii R and R ' = 3.00R, that lie on the same plane. Point P lies on the central z axis, at distance D = 2.00R from the center of the rings. The smaller ring has uniformly distributed charge +Q. What must be the uniformly...
  31. J

    Determining U(Z[x]) & U(R[x]) Rings

    I am having a problem with some abstract algebra and I was wondering if anyone could help and give me some insight. The problem is as follows: Give an explanation for your answer, long proof not needed: Determine U(Z[x]) Determine U(R[x]) These are in regards to rings. I know...
  32. D

    Energy Acceptance in Electron Storage Rings

    I'm working on a research project involving calculations about various aspects of electron storage rings and have come across the term energy acceptance or energy aperture. Could someone explain to me what is meant by this term? It is used in a lot of literature but I haven't been able to find a...
  33. S

    Effect of a pair of slip rings in a DC motor

    Effect of a pair of slip rings in a DC motor Hi, I have a question here. Knowingly that the effect of a slip ring in a DC motor is to reverse the direction of the current in a loop whenever the commutator changes contact from 1 brush to another, so as to ensure the loop to be always...
  34. M

    Moment of Inertia of Solid and Hollow Spheres using Disks and Rings Respectively

    Whilst following my textbooks advice and "proving to myself that the inertia listed are true" I considered the Moment of Inertia of a hollow sphere by adding up infinitesimally thin rings: dI = y^2 dm = y^2 \sigma dS = y^2 \sigma 2\pi y dz = 2\pi y^3 \sigma dz This didn't work...
  35. Z

    Factorization of rings problem

    Homework Statement in order to factorize 20 on the rings of Q( \sqrt 2) i must solve Homework Equations x^{2} -2y^{2}=10 The Attempt at a Solution i do not know how to solve it, i have tried by brute force with calculator but can not get any response , the given hint is that...
  36. C

    Finite Commutative Ring: Proving Integral Domain w/ No Zero Divisors

    Homework Statement Show that a finite commutative ring with no zero divisors is an integral domain (i.e. contains a unity element) Homework Equations If a,b are elements in a ring R, then ab=0 if and only if either a and b are 0. The Attempt at a Solution I've been trying to use...
  37. H

    Rings, finite groups, and domains

    Homework Statement Let G be a finite group and let p >= 3 be a prime such that p | |G|. Prove that the group ring ZpG is not a domain. Hint: Think about the value of (g − 1)p in ZpG where g in G and where 1 = e in G is the identity element of G. The Attempt at a Solution G is a...
  38. A

    Calculating the Dipole Moment of Benzene Rings

    Hi , How to calculate the diploe vector of benzene ring?. what is the formula for calculating the diploe moment?. Thanks in advance Aneesh
  39. G

    Ideal Rings - Abstract Algebra

    Homework Statement Suppose R is a ring and I,J is an ideal to R. Show (i) I+J is ideal to R. (ii) I union J is ideal to R.Homework Equations none
  40. J

    Formula for Area of Overlapping Rings?

    Could anyone direct me to a formula for the area enclosed by two overlapping rings? Sketch below... Thanks... -jg
  41. F

    Saturn's Rings: Why Are They Split?

    Why are Saturns rings broken up into many rings? Why don't they all just orbit together in one massive ring.
  42. P

    How Do Cosets in the Gaussian Integer Ring Relate to Its Ideals?

    Hi so this isn't homework its in my book , i just don't get it they skipped this step Let R=Z(i) be the ring of gaussian integers and let A=(2+i)R denote the ideal of all multiples of 2+i Describe the cosets of R/A im just having trouble understaning this step: "Since 2+i is in A we...
  43. D

    Rings and Homomorphism example

    Homework Statement Give an example of a ring R and a function f: R---->R such that f(a+b)=f(a)f(b) for all a,b in R. and f(a) is not the zero element for all a in R. Is your function a homomorphism? Homework Equations Let R and S be rings. A function f:R----->S is said to be a...
  44. E

    Building a Paper Bridge: Connecting the Rings and Deck

    We are trying to build a bridge made from paper, water based glue and cotton strings. The bridge must be able to hold 5kg; however, we would like it to hold more weight. The weight of the bridge should also be taken into consideration. So we came up with numerous designs and we finally...
  45. C

    Solving Rings and Idempotent Problems - RK

    I have a tablet so I have made a PDF of all my work and the problem. the file is attached to this post. please let me know if i am on the right track or give me a hint. I am currently stuck in attempt 2 and don't like my solution in attempt 1. attempt 1: at the very last step I am using...
  46. R

    Civilization of millions of rings.

    Ruslan A. Sharipov. Future forecast. Essay. Typically SiFi writers and futurologists make their forecasts for future. Now I am joining them with my own forecast. It is an entrenched habit to show the future equipped magic tools like antigravitators and space-time gates. One can see them...
  47. S

    General confusion about quotient rings and fields

    Homework Statement I'm having a hard time understanding quotient rings. I think an example would help me best understand them. For example, how does the ring structure of \mathbb{F}_{2}/(x^4 + x^2 + 1) differ from that of \mathbb{F}_{2}/(x^4 + x + 1)? Homework Equations The...
  48. U

    Launching a Small Ball: Targeting Rings & Floor

    Homework Statement i'm launching a small ball from a launcher (on a table) at 55 degrees into rings (at .25, .50, .75, 1) and to a target on the floor. height from the floor to the launcher: 1.015m angle: 55 velocity: 6.62 m.s i have to find how far each ring will have to be from the...
  49. S

    How to show two rings are not isomorphic

    I'm just beginning my study of rings, and I'm wondering if there are some standard ways to show that two rings are not isomorphic. I've studied groups quite a bit and I know some of the ways to show that two groups are not isomorphic (G contains an element of order 2 while G' contains no...
  50. M

    Proving Uniqueness of Products in Finite Rings

    Homework Statement Let q be the number of units in finite ring R. Show that for all a in R, if a is a unit in R then a^q = 1. Is there a way to solve this without using group theory? All I can seem to find information on is when a and m are relatively prime then a^{\phi (m)} = 1 (mod \, m)...
Back
Top