Elements Definition and 1000 Threads

  1. E

    MHB Exploring the Periodicity of Powers in Modular Arithmetic

    This is a basic question about the behavior of $a^k$ for $a\in\mathbb{Z}/n\mathbb{Z}$ and $k=1,2,\dots$. I know that Fermat's little theorem says $a^{p-1}=1$ in $\mathbb{Z}/p\mathbb{Z}$ for prime $p$; thus, the sequence $1,a,a^2,a^3,\dots$ is periodic with period at most $p-1$. More generally...
  2. S

    A Calculation of S-matrix elements in quantum field theory

    Consider the following extract taken from page 60 of Matthew Schwartz's 'Introduction to Quantum Field Theory':We usually calculate ##S##-matrix elements perturbatively. In a free theory, where there are no interactions, the ##S##-matrix is simply the identity matrix ##\mathbb{1}##. We can...
  3. C

    I What's the Difference Between Zero Divisors and Torsion Elements?

    So I've been studying advanced linear algebra and have started learning about modules. However, I am having a hard time understanding the difference between a zero divisor and a torsion elements. The definitions seem extremely similar. Can someone offer a good definition of each and an...
  4. RJLiberator

    Two conjugate elements of a group have the same order PROOF

    Homework Statement Let x and y be conjugate elements of a Group G. Prove that x^n = e if and only if y^n = e, hence x and y have the same order. Homework Equations Conjugate elements : http://mathworld.wolfram.com/ConjugateElement.html The Attempt at a Solution Since y is a conjugate of x...
  5. M

    MHB Why Are Nilpotent Elements Significant in Ring Theory?

    Hey! :o I am looking at the following exercise: An element $r\in R$ is called nilpotent if $r^n=0$ for some integer $n=1,2, \dots $. Show that if $r$ is nilpotent then $1-r$ is invertible in $R$. Show that if $R$ is commutative then the set $N(R)$ of nilpotent elements is an ideal of...
  6. M

    MHB List the elements of the field F = F3[x] / < x2 + 1 >

    Can someone please explain the deconstruction and elements of this set. I understand it to be.. F3[X] = {f(x)=a(0)+a(1)X+...+a(n)X^n : a(i) in F3] <x^2+1> = {g(x)(x^2+1): g(x) in F3[x]] So an element in the quotient should be something like f(x)+<x^2+1> Yet, research shows there are nine...
  7. kamhogo

    Light bulb & Diode: linear or non-linear elements.

    Homework Statement These questions are related to an experiment where we had to record the current for varying values of potential difference (10 readings), then repeat the process with the applied potential difference was reversed a) Why is the resistance of a light bulb not constant? b) Does...
  8. xwolfhunter

    B Reading Legendre's Elements of Geometry

    In discussing proportions (a topic to which I have not been properly exposed) Legendre states that, adding the antecedent of a proportion to the consequent, and comparing the sum to the antecedent, one obtains a proportion equal to the original plus unity. Legendre's book is apparently...
  9. C

    B Can all elements, (not including gases) form Ionic Bonds?

    I've been looking all over the internet, can calcium and iron form an ionic bond, Gold and Radium, Sodium and Tin. If those elements happened to run into each other. Also, another thing I don't understand is why don't the atoms in my hand bond with atoms on the wall when they come into contact.
  10. N

    MHB How to Modify Vector Elements to Double Values Less Than a Minimum?

    I don't understand how it able to skip one element to the other in order to multiply the numbers by 2. It be helpful if anyone can explain.Double any element's value that is less than minVal. Ex: If minVal = 10, then dataPoints = {2, 12, 9, 20} becomes {4, 12, 18, 20}. #include <iostream>...
  11. N

    C/C++ How to decrement vector elements and handle negative values in C++.

    I am stuck on now to decrement the numbers and would like some help please. Write a loop that subtracts 1 from each element in lowerScores. If the element was already 0 or negative, assign 0 to the element. Ex: lowerScores = {5, 0, 2, -3} becomes {4, 0, 1, 0}. #include <iostream> #include...
  12. Docscientist

    Electronic configuration of transition elements

    I know about quantum numbers and how we do it as 1s,2s,2p,3s,3p,3d etc...but how do I find the number of valence electrons by doing this ? I watched so many videos about this topic and I still don't get it.Possibly because I am trying to learn the portions before even it is taught at school.Can...
  13. C

    I Do more unstable elements decay faster than more stable ones?

    Do more unstable elements decay faster than more stable ones? Thanks!
  14. O

    MHB Trouble Printing Out Array Elements with a For Loop

    I am having problems with printing out each elements of the array using a for loop It's suppose to look like this: Enter non-negative numbers (ints) terminated by -99 1 2 3 4 5 6 -99 Original list (6 values): 1, 2, 3, 4, 5, 6. the code's output looks like: Enter non-negative numbers (ints)...
  15. F

    Max thermal conductivity required for heating elements

    I'm designing an oven and want to ensure that the insulation I specify has a low enough Thermal Conductivity (k) to resist excessive heat loss. I determine heat loss (Hout)with the following equation: Hout=A*U*(T1-T0). U is dependent on k (U=k/L). I omitted the heat transfer coefficient in...
  16. dwdoyle

    Degenerate Perturbation Theory and Matrix elements

    Homework Statement I did poorly on my exam, which I thought was very fair, and am now trying to understand certain aspects of perturbation theory. There are a total of three, semi related problems which i have questions about. They are mainly qualitative in nature and involve an intuitive...
  17. P

    Passive vibration suppression using piezoelectric elements?

    I am looking at one idea to passive vibration supression that involves "a resistive shunt to a piezoelectric material" but I can not find a lot of info outside of papers that I would have to pay for. does anyone know and can explain some detail about this method?
  18. memoryerasure1

    B In glass, the elements that make it up, like silicon, and so

    In glass, the elements that make it up, like silicon, and sodium. Does the electron eV levels change as these elements become molecules [PLAIN]http://www.chemicalforums.com/Smileys/classic/grin.gif, and become solid glass. To put it another way, if silicon, sodium, and calcium atoms which have...
  19. S

    I Can someone define what a tuple is for me?

    Ok, so I read that a tuple is an ordered list of n elements, where n is a non-negative integer. Sometimes I get confused with tuples and partially ordered sets. So if I organized a list of all the airplanes in a particular airport, would that be a tuple, or would that be a set? I'm leaning...
  20. M

    MHB The probability that two elements commute

    Hey! :o Let $G$ be a finite group. I want to show that the probability that two elements of $G$ commute is $\frac{m}{|G|}$, where $m$ is the number of conjugacy classes of $G$. A conjugacy class is $O_x=\{g*x\mid g\in G\}=\{g^{-1}xg\mid g\in G\}$, right? (Wondering) Do we maybe take $x$...
  21. epenguin

    Elements of truth - Moseley, Bohr, recognition and teaching.

    There is no longer a history section in PDF, but this is not suitable for any speciality forum. Just yesterday*, as usual a step ahead and with uncanny prescience, I was recommending a student to familiarise himself with Moseley's law as reinforcement and more in the learning of atomic physics...
  22. G

    MHB Every set of k+1 elements is dependent.

    Let $S = \left\{x_1, \ldots, x_k\right\}$ be independent set consisting of k elements in a linear space V and let $l(S)$ be the subspace spanned by $S$. Then every set of k+1 elements in l(S) is dependent. I've gotten nowhere with this - but I'm posting my attempt nonetheless if only for the...
  23. Prins

    Which are the elements which direcly sublimes

    I know that Arsenic sublimes directly when heated. So I want to know which other elements like this sublimates on heating throughout the periodic table. I also know dry ice. thanks
  24. EinsteinKreuz

    Creating a Grid w/Square Elements for a Cayley Table

    Is there a way to create a grid here on PF that has square elements? I ask because I'm yearning to make a post that will require a Cayley table.
  25. M

    MHB What Do the Elements of $\mathbb{Z}_2 \times \mathbb{Z}$ Look Like?

    Hey! :o To show that in the additive group $\mathbb{Z}_2\times\mathbb{Z}$ there are non-zero elements $A,B$ of infinite order such that $A+B$ has finite order, we have to find such $A$ and $B$, right? (Wondering) How do the elements of $\mathbb{Z}_2\times\mathbb{Z}$ look like? (Wondering)
  26. T

    Machine elements stress concentration

    Homework Statement A flat part with constant thickness b is loaded in tension as shown. The height changes from 50 to 87 mm with a radius r = 4.0 mm. Find how much lower a load can be transmitted through the bar if the height increases from 50 to 100 mm and the radius increases from 4.0 to 10...
  27. E

    How Many Elements Exist If n <= 4?

    Homework Statement If elements with principal quantum number n > 4 were not allowed in nature, the number of possible elements would be (A) 60 (B) 32 (C) 4 (D) 64 Homework EquationsThe Attempt at a Solution I got 36 from the periodic table (2+8+8+18) However, that isn't even an option. The...
  28. C

    How Are Mean Orbital Elements Calculated?

    Good morning, I was making some investigation regarding the calculation of mean orbital elements - not osculating. Is this done simply by fitting (with the best equation) several osculating elements across time, or is there a mathematical approach already settled? Cheers,
  29. T

    Machine elements - deflection and stress problem

    Homework Statement Homework Equations δ = Pl/AE σ = P/A The Attempt at a Solution I had calculated the deformation for both the steel and aluminum, and added them together to give me δ = 0.481 mm, which is incorrect. I also thought I could simply plug in the force P = 200kN and the...
  30. mnb96

    Elements of semigroup commuting with subgroup

    Hello, Suppose we have a semigroup S with a subgroup G≤S. Assume there is an element s∈S that commutes with all the elements in G. Does this statement implies (or is equivalent to) another statement? If hypothetically the element s would have been in G, then we could have said that s was an...
  31. sciencejournalist00

    What is the role of these elements in entanglement

    Sorry to disturb you again, but I thought of what you said in my previous questions. Dichroic mirrors, polarizers are used in the above entanglement experiment but according to their encyclopedic definition, they only filter light by color and polarization. Half-wave plates and quarter-wave...
  32. anorlunda

    The Mystery of Elements in the Sun's Primordial Dust Cloud

    Today's APOD http://apod.nasa.gov/apod/ap160125.html Shows this fascinating table. What a pity that is doesn't show isotopes. Strange are Ba, La, Ce which are shown as large star but not supernova. The article says that the origin of Cu is not well known. Fascinating. I'm curious about the...
  33. CFDFEAGURU

    ANSYS Workbench and MESH200 Elements: EMODIF

    Hello all, I have been doing a number of analysis that require the use of Workbench and Spaclaim and Classic (APDL). SpaceClaim is used to bring in the geometry and defeature it and to create the proper components with elimination of contacts thru the use of the Share Topology feature. This is...
  34. T

    What do you call elements below metalloids?

    What do you call metals under metalloids on the periodic table? Since they arent metalloids nor transition metals. Do they have a specific name? Thanks!
  35. A

    The rigor of using differentials in line elements

    Greetings all, In Hartle's Gravitation, it seems like a given the way he manipulates the "differentials" when he gives a line element. The thing is that it works, and I know it's not mathematically rigorous, but first of all, I'm wondering when treating the differentials in the line elements in...
  36. T

    Matrix elements of non-normalizable states

    Although strictly quantum mechanics is defined in ##L_2## (square integrable function space), non normalizable states exists in literature. In this case, textbooks adopt an alternative normalization condition. for example, for ##\psi_p(x)=\frac{1}{2\pi\hbar}e^{ipx/\hbar}## ##...
  37. L

    What are the elements of Lie algebra in the case of a single generator?

    Elements of Lie algebra are generators. So for example Pauli matrices are generators of rotation and the elements of Lie algebra. And multiplication in Lie algebra is commutator. Right? What about if there is only one generator. As in case in rotation in plane. What is Lie algebra product in...
  38. GiantSheeps

    Naturally occurring elements yet to be discovered?

    So I know that all the elements above 92 on the periodic table do not occur naturally, does that mean that we've discovered all the naturally occurring elements? Is it possible that there can be elements with a higher atomic number than 118 that we just haven't discovered yet in nature?
  39. X

    Could NMR be applied for other elements besides Hydrogen?

    Most books discribe NMR as a diagnotic technique for Hydrogen and its isotopes. Could Nuclear Magnetic Resonance Spectroscopy be applied for other elements with odd atomic number besides H? If so, what is the major challenge for a multi-element scanning?
  40. A

    Under ideal conditions could there be thousands of elements?

    Right now I think there's 118 elements. If somewhere in space it was a certain temperature, with certain pressure, and other certain factors, could there be more elements. Let's say these conditions are too extreme to be made on Earth like a Trillion degrees Celsius. So if there were there...
  41. chikou24i

    Understanding C=(2*C5): Elements and Meaning

    One of the classes of the group C5v is written C=(2*C5). So why do we mean by 2*C5 and how we can know the elements of this class from this writing ? Thanks
  42. B

    I Why can sets contain duplicate elements?

    If S={a,b,c}, what does it mean that S=T when T={a,a,a,a,a,a,b,c}? The mapping that confirms the definition of equality assumes that the duplicate symbols in a set are representative of the same entity or idea. If S={1/2} and T={ .5 , 2/4 , ,25/,5 , 4/8 } are these sets equal? At what point...
  43. Z

    How many elements does the set A union B have?

    Homework Statement A and B are both spans. A = span(a1,a2,a3) B = span(b1,b2) Then how many elements would AUB have? Homework Equations N/A The Attempt at a Solution [/B] I'm almost certain the answer is 2, with the two elements being span(a1,a2,a3) and span(b1,b2) but I'm unsure as to...
  44. M

    Proof with sets and elements. Am I going about this right?

    Homework Statement Give an element-wise proof for the following: If A⊆B and B⊆C', then A ∩ C = ∅ Homework Equations A is a subset of B (written A ⊆ B) if every element in the set A is also an element in the set B. Formally, this means that fore every x, if x ∈ A, then x ∈ B. A ∩ B = { x ∈ U ...
  45. askhetan

    Matrix Elements as images of basis vectors

    I'm trying to understand the maths of QM from Shankar's book - Principles of Quantum Mechanics: On page 21 of that book, there is a general derivation that if we have a relation: |v'> = Ω|v> Where Ω is a operator on |v> transfroming it into |v'>, then the matrix entries of the operator can be...
  46. C

    Computing osculating orbital elements

    Good afternoon, I wonder if someone can help me in a small doubt. I'm trying to calculate the orbital parameters of some solar system bodies. It's quite easy knowing their positions and velocities. But my question is this: these two components, position and velocity, must they be heliocentric...
  47. M

    Understanding Voltage Drops and KVL in Circuit Analysis

    p here stands to power (v in power equation is magnitude), in addition to this : is it also true that in the first one : V = RI (V upper - V lower) and in the second one : V = - RI (V lower - V upper) ? (current is magnitude in all previous equations)
  48. B

    "Periodic table" of combined elements

    The periodic table is globally known! But, it relates EACH element separately! Exist some table, some lists, some spreadsheet, etc, that relates the combinations between the elements and give us the information about each combination? PS: for "combined elements" I want to say simples substance...
  49. Activeuser

    Ladder operators and matrix elements...

    Please I need your help in such problems.. in terms of ladder operators to simplify the calculation of matrix elements... calculate those i) <u+2|P2|u> ii) <u+1| X3|u> If u is different in both sides, then the value is 0? is it right it is 0 fir both i and ii? when exactly equals 0, please...
  50. O

    Solving KVL: Voltage Across All Elements

    Homework Statement Determine the voltage across all elements Homework Equations i=v/r v1+v2+v3+..=0 The Attempt at a Solution I'm not sure which of the nodes I should use to take my KVL from. The a and b are labeled, but should I combine the set of 2-6-6 resistors and label that as an...
Back
Top