Rings Definition and 418 Threads

  1. J

    Newton's Rings Problem: Determining Thickness of Film for 6250 A Light Rings

    Homework Statement If the apparatus for showing Newton's rings is illuminated with light at 6250 A (angstroms), what thickness of film underlies each of the first three light rings? Homework Equations 2D (the thickness of the film) equals a multiple of 1/2 of a wavelength 1 angstrom =...
  2. S

    What Causes a Bright Spot at the Center in a Newton's Rings Experiment?

    Homework Statement In a Newton's Rings experiment, involving a curved lens on a glass surface, what might have happened to the set-up to see a bright spot at the centre? 2. The attempt at a solution Well I know that normally we get a dark spot at the centre because of the lambda/2 phase...
  3. quasar987

    Algebra question - rings and ideals

    [SOLVED] Algebra question - rings and ideals Homework Statement Let R be a (nonzero) commutative ring with identity and I be an ideal of I. Denote (I) the ideal of R[x] generated by I. The book says that (I) is the set of polynomials with coefficients in I. Why is that? The Attempt at a...
  4. C

    Is Idempotent Equivalence in Rings Transitive?

    One of my books defines a relation which is "evidently" an equivalence relation. It says that two idempotents in a ring P and Q are said to be equivalent if there exist elements X and Y such that P = XY and Q = YX. The proof that this relation is transitive eludes me. There is so little...
  5. Simfish

    Generating Rings with Ideals: The Possibilities and Implications

    Do all rings have to be generated by ideals? Or can some rings come without ideals? Can some elements in rings be generated by ideals (in ways that other elements of rings are untouched by ideals?) If ALL of a ring's elements are generated by ideals, is there something special about the...
  6. E

    Ring with Unity: Subrings Isomorphic to Z & Z_m

    [SOLVED] rings with unity Homework Statement Corollary 27.18 (in Farleigh) tells us that every ring with unity contains a subring isomorphic to either Z or some Z_n. Is it possible that a ring with unity may simultaneously contain two subrings isomorphic to Z_n and Z_n with n not equal to m...
  7. E

    What Are Guard Rings for IC Inputs and How Do They Improve Noise Rejection?

    What are these? Is it like some 'physical ring' where you out a wire through it or just a connection to make both input to the op-amp common? How does this really help? Seems like you're making a source common to both like gnd so if the gnd is noisy it becomes common for both and rejects it...
  8. I

    Why Use a - b Instead of a + b in Equivalence Classes of Rings?

    So I'm kind of confused about the definition: a-b\in I Why a - b instead of a + b?
  9. P

    Saturn Rings: Age and Permanent Feature

    Hi all, I have read this article about Saturn rings: http://www.space.com/news/ap-071213-saturn-ringage.html The author argues as: Quotes: "The notion that Saturn's rings may be a permanent feature was based on observations by the ultraviolet spectrograph instrument on Cassini, which...
  10. C

    What Do Homomorphisms on Rings Really Mean?

    can someone please explain what these mappings really means? like what is being mapped and mapped to..?? i get confused by the direct sum & product that gets mapped.. Z \oplus Z ->Z Z -> ZxZ
  11. Z

    Surjective Homomorphisms of Coordinate Rings

    Homework Statement I want to show that the homomorphism phi:A(X)->k+k given by taking f(x_1,...,x_n)-> (f(P_1),f(P_2)) is surjective. That is, given any (a,b) in k^2 (with addition and multiplication componentwise) I want to find a polynomial that has the property that f(P_1)=a and f(P_2)=b...
  12. P

    A question about the Satturn rings.

    Hi all, my question is: -Are there any possibillities that the rings around Satturn will become satellites one day? Thank you.
  13. quasar987

    Boolean rings and Boolean algebras

    My professor wrote that we get a Boolean algebra from a Boolean ring (R,+,-,.,0,1) by setting xANDy=xy, xORy=x+y+xy and xNOT=1+x. But it seems to me that xNOT is not an involution. I.e., (xNOT)NOT = 1+(1+x), which is not x. (xNOT=-x would do the trick though)
  14. P

    Is the Diamond Lemma related to representation theory in Hopf algebras?

    Anyone know that result? Comments? How is it connected to algebra in general and what kind of algebra is it part of? It is obviously about rings but what else is it part of?
  15. L

    How can I find the minimum volume of two rings in soap water with given radii?

    Two rings with radius R and r are let down in the soap water. Between them pellicle appeared (like in image). Image: here all are symmetric ;) problem: need to find y=f(x) what i think:volume of figure is minim. maybe express volume via needed function, then get minimum of volume, and find...
  16. L

    Are all (q) prime ideals in Z(\rho)?

    This is the last question in Elements of Abstract Algebra by Allan Clark. When is (q) a prime ideal in Z(\rho) (the Kummer ring) where \rho = e^{2\pi i /p}, where p and q are rational primes. This seems to be a difficult question to answer in general... since considerable effort goes into...
  17. M

    Commutative rings with identity

    I have a trouble proving that a finate (nonzero) commutative ring with no zero divisors must have an identity with respect to multiplication. Could anybody please give me some hints? I do know all the definitions (of ring, commutative ring, zero divisors, identity) but have no idea how to go...
  18. Z

    Proving Injectivity of Surjective Ring Homomorphism in Noetherian Rings

    Suppose A is a Noetherian ring, phi:A->A any surjective ring homomorphism. Show that phi is also injective. Also, if all the prime ideals of a ring A are finitely generated then is A noetherian? I'm pretty sure it is. I figure I can take all of the ideals that are not finitely generated...
  19. C

    Why Does the Field Choice Affect Maschke's Theorem Application to Group C2?

    In the statement of Maschke's theroem we are told 'Let G be a finite group and F a field in which |G| not equal to zero. As an example we are told if our group was C2 (cyclic) then we could not have F=F2 (the field with 2 elements). I fail to see how C2 and F2 are related, surely |C2|=2...
  20. Q

    Proving Isomorphism without Explicit Functions in Abstract Algebra

    I am having a very hard time with a general concept of proving something. If I have some arbitrary function mapping one ring, let's say R, to another ring, S, and want to prove that R is isomorphic to S, then I need to show that there exists a bijective homomorphism between R and S. But how do I...
  21. R

    GCD of a & b in Ring R: Unique or Not?

    [b]1. I am just looking for a defn, I can't find it on the net: Given a ring R, a, b elements of R, (a?) gcd(a,b) is defined to be? [b]3. I am guessing that if d/a and d/b and for any other e such that e/a and e/b we have e/d, then d is (a?) gcd of a and b. Is this correct, and is...
  22. S

    Newton's Rings and plano-convez lens

    Homework Statement A plano-convez lens (flat on one side, convez on the other) rests with its curved side on a flat glass surface. The lens is illuminated from above by light of wavelength 521 nm. A dark spot is observed at the centre, surrounded by 15 concentric dark rings (with bright rings...
  23. P

    Im soooooo close to solving this problem (Rings)

    Question: Let R be a ring of characteristic m > 0, and let n be any integer. Show that if 1 < gcd(n,m) < m, then n · 1R is a zero divisor heres what i got out of this: Let gcd(n,m) = b 1< d < m so m/d = b < m and d | n Also, m * 1_R = 0 can someone please offer some...
  24. P

    Im soooooo close to solving this problem (Rings)

    Let R be a ring of characteristic m > 0, and let n be any integer. Show that: if 1 < gcd(n,m) < m, then n · 1R is a zero divisor heres what i got out of this: Let gcd(n,m) = b 1< d < m so m/d = b < m and d | n Also, m * 1_R = 0 can someone please offer some insight...
  25. T

    How many bright rings are produced in Newton's Rings experiment?

    Figure 35-46a shows a lens with radius of curvature R lying on a flat glass plate and illuminated from above by light with wavelength . Figure 35-46b, a photograph taken from above the lens, shows that circular interference fringes (called "Newton's rings") appear, associated with the variable...
  26. A

    Rings, ideals and Groebner basis

    How does a Goebner basis relate to Ideals and how does it help solve otherwise extremely complex systems of equations? Part of what I'm working on involves trying to solve V=0=\partial_{i} V for V a quotient of polynomials in several variables. This paper talks about using the Groebner basis...
  27. P

    Boolean rings with identity can only take 2 elements?

    Using the theorem that in any boolean ring a+a=0 for all a in boolean ring R. Then 0 is in R. Make the multiplicative identity 1 is also in it. Therefore R can only take 0 and 1 and no more because 1+1=0. 0+0=0. 1+0=1 always. So 2 or other elements can never occur.
  28. P

    What Is the Connection Between Quotient Rings and Division?

    Quotient ring is also know as factor ring but what has it got to do with 'division' in any remote sense whatsoever? I know it is not meant to be division per se but why give the name of this ring the quotient ring or factor ring? What is the motivation behind it? R/I={r in R| r+I} Normally...
  29. C

    Isomorphic Polynomial Rings in F_5[x]

    Homework Statement I am required to prove that F_5[x]/(x^2 + 2) isomorphic to F_5[x]/(x^2 + 3) now I have the solution in front of me so I more or less know what's going on, however there are some points of confusion... ...the solution states that x \rightarrow 2x will define the...
  30. C

    Are F5[x]/(x^2 + 2) and F5[x]/(x^2 +3) Isomorphic Polynomial Rings?

    I am required to show that F5[x]/(xsqd + 2) and F5[x]/(xsqd +3) are isomorphic, any hints on how to go about this question?
  31. P

    Cosets in Rings: Sets {a*R} & {a+R}

    Does cosets exist in rings? i.e R = Ring, a in R set {a*R} or set {a+R} The above two sets looks very similar to cosets in groups but there are two operations in rings so potentially two different cosets both involving the same ring R and element a. If the above two sets are not...
  32. B

    What are Saturn's rings made of and how are they formed?

    I know this isn't really 'earth sciences' but there is no planetary forum that I am aware of. Anyway, why does Saturn have rings, and what are they made of? I read somewhere that Enceladus is the major souce of Saturn's largest ring, the 'E-ring'. What does that mean...
  33. C

    Unital rings, homomorphisms, etc

    I've already completed 1), but it's necessary for one to know it for question 2). I'm pretty sure that I've found my homomorphism in 2, but I don't know whether or not is unique. How do I show a homomorphism is unique in this case? Problem 1: Let R be a commutative unital ring, and let S be a...
  34. G

    Finding units in polynomial quotient rings

    Is there a simple method for finding all the units in a polynomial quotient ring over a finite field? For example: {F_2[x] \over x^7-1} I can see the easy ones like 1, and all power of x, but I wanted a general rule or method for finding all of them if it exists (besides testing each...
  35. H

    Figuring sum of double bonds and rings ?

    Figuring sum of double bonds and rings ?? Does anyone know how if there is a way to figure out the sum of double bonds and rings of a compound C6H9BrO ?? Lost.. thank you.
  36. Mk

    How reliable are tree rings for climate modeling?

    I won't say who said it, but does this sound right to you? Dendrochronolgists on TV all say it so easy, you count the tree rings and the space in between, and that will tell you about the temperature and precipitation and how long the tree lived. Also: This sounds kind of dumb, but what about...
  37. K

    Help with Newton's Rings Homework Questions

    Hi. I have some homework questions here that I need a little help on. I know the fomulae to use just do not know how to apply it properly. Any help will be appreciated. In a Newton's Ring experiment, a planoconvex glass (n=1.54) lens having a diameter 14.3 cm is placed on a flat plate. When...
  38. Astronuc

    NASA NASA's Hubble Discovers New Rings and Moons Around Uranus

    http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/33/full/
  39. T

    Homeomorphism of Rings: Proving Existence for Prime Numbers p and q

    Let p,q be two prime numbers. Prove that there exists a homeomorphism of rings such that f([1]_p)=[1]_q from Z_p[X] into Z_q[X] if and only if p=q. I believe that the converse of the statement is trivial but the implication seems to be obvious? I really don't know what there really is to...
  40. L

    Contact between two rings or two cylinders

    Hello, I would be interrested in comments, references, books, papers and web pages regarding the problem of mechanical contact between two rings. The attached picture describes the geometry of the problem: a ring (tube) is resting on the bottom of a larger ring (tube). These two rings are...
  41. C

    Saturn's Rings Shifting: New Findings

    http://hosted.ap.org/dynamic/stories/S/SATURN_RINGS?SITE=TNNAT&SECTION=HOME&TEMPLATE=DEFAULT
  42. A

    The hoard of the Rings: Zaentz gets 168 million dollars

    Some of the squabbles over how the immense profits from the "Lord of the Rings" are to be divided, have now been settled out of court, according to this article: http://news.independent.co.uk/world/americas/article309203.ece Still, a lot of quarrels remain; in particular, Peter Jackson&Fran...
  43. E

    Rings on high voltage connectors?

    Hi all, I'd like to know what these rings at high voltage connectors are good for: http://www.surplec.com/hvt_polemount_shipping.jpg http://www.surplec.com/hvt_inventaire_15.jpg http://www.recursivemediaone.com/high%20voltage%203%20gs.jpg
  44. P

    Solving the Temperature Difference for Steel & Aluminum Rings

    A steel sphere sits on top of an aluminum ring. The steel sphere (a (average coefficient of linear expansion) = 1.1*10^-5/C) has a diameter of 4 cm at 0 C. The aluminum ring (a = 2.4*10^-5/C) has an inside diameter of 3.9940 cm at 0 C. Closest to which temperature given will the sphere...
  45. E

    Discover the Secret to Creating Perfect Smoke Rings | Ssss Smokin Smoke Rings

    The Other Day I Was Sitin In A Bar Looking At My Freinds Smoking , They Tried And Tried To Blow A Smoke Ring But Could'nt ,it Ws Agreed That Its Not Possible To Create Smoke Rings At Will ,its A Flash In The Pan , But I Differed ,surely Their Must Be Some Condition For Creating A Smoke Ring ,i...
  46. B

    Visualizing the Associative & Distributive Properties of Rings

    I'm just starting rings and I don't think I really understand them. When an operation is shown as a grid where the entry i, j in the grid is the element (i op b), I can see immediately what the commutative property looks like (grid symmetric about diagonal from top left) and what a unit, a...
  47. S

    Is it possible for a Rocky Giant with rings around it?

    Most giant planets we know of are Gas Giants. Is it possible for a planet made of rocks to be the size of jupiter? In other words is it possible for a Rock Giant? Also, is it also possible for a rocky planet to have rings around it like Saturn? Though we have found no rocky planet with rings...
  48. jma2001

    Lord of the Rings: an allegory of the PhD

    Those of you stressing over grad school should read this ... funny stuff. (I am not the author, by the way, I just found it amusing). http://www.livejournal.com/users/capthek/224706.html
  49. C

    Do Fans of Lord of the Rings Enjoy Playing Kings of Chaos and Utopia?

    ...then you'll probably like playing this: Kings of Chaos
  50. M

    How Accurate Are Mood Rings in Reflecting Emotions?

    I don't really know where this thread belongs. I trust the mentor to move it, if necessary. How do mood rings work? How accurate are they? As always, any and all relevant information is appreciated.
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