What is Elements: Definition and 1000 Discussions

Éléments is a French bi-monthly magazine launched in September 1973 and associated with the Nouvelle Droite.
With a social and European inspiration, the magazine promotes a critical vision of liberal modernity on topics such as localism, ecology, respect for cultural diversity and the defence of European identity.

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  1. H

    Chemistry Chemistry: Elements, Molecules and Bonds

    Homework Statement For a biology lab dealing with chemistry, we are supposed to make models (ball and stick) of molecules, and then we need to write the structural and molecular formulas. The models should represent single or double bonds based on the molecular composition. The problem is...
  2. B

    On the sums of elements of uncountable sets

    I want to prove the following proposition: Given any uncountable set of real numbers S, there exists a countable sub-collection of numbers in S, whose sum is infinite. Please point me in the right direction.
  3. mnb96

    Permutations of basis elements in Clifford Algebras

    Hello, let's consider, for example, the Clifford algebra CL(2,0) and the following mapping f for an arbitrary multivector: a + b\mathbf{e_1}+c\mathbf{e_2}+d\mathbf{e_{12}} \longmapsto a\mathbf{e_{12}} + b\mathbf{e_1}+c\mathbf{e_2}+d For vector spaces R^n we can permute the coordinates of...
  4. S

    Modern Algebra-Proving Elements Conjugate

    1. If a1,...,an is a list of (not necessarily distinct) elements of a group G, then, for all i, ai...ana1...ai-1 is conjugate to a1,...,an. Homework Equations The Attempt at a Solution I know that you have to prove the existence of an element g of the group G such that...
  5. B

    Matrix elements of one-body operator

    Homework Statement Consider two fermion states: |n_1 n_2\rangle = a_{n_1}^\dagger a_{n_2}^\dagger|0\rangle and |n_1 n_3\rangle = a_{n_1}^\dagger a_{n_3}^\dagger|0\rangle where a_n^\dagger denotes the fermion creation operator in the single-particle state u_n\left(\vec{r},s\right)...
  6. C

    Rings and Fields - Write down the nine elements of F9

    Rings and Fields - Write down the nine elements of F9[i] Homework Statement In F9 = Z/3Z, there is no solution of the equation x^2 = −1, just as in R. So “invent” a solution, call it 'i'. Then 'i' is a new “number” which satisfies i^2 = −1. Consider the set F9[i] consisting of all...
  7. Y

    Largest GCD of consequtive elements in a sequence.

    Say I have a sequence a(n) = 100 + n^2 with n ranging through the positive integers. I want to find the largest number g(n) such that g(n) = gcd(a(n), a(n+1)). Let g be a number that divides both a(n) and a(n+1) g | 100 + n^2 and g | 100 + n^2 + 2n + 1 therefore g | 2n + 1. This means that g...
  8. 1

    Proving an Abelian Group with 2 Elements of Order 2 has a Subgroup of Order 4

    Homework Statement Prove that an abelian group with two elements of order 2 must have a subgroup of order 4 Homework Equations The Attempt at a Solution Let G be an abelian group ==> for every a,b that belong to G ab=ba. Let a,b have order 2 ==> a^2 =e and b^2 = e. Since a...
  9. S

    A circuit of four elements. Which are in series and which are in parallel?

    I basically have this diagram: http://www.tinyimg.org/images/595physic144.png The problem asks "which of the elements are in series and which of the elements are in parallel?" I WANT to say that they are ALL in parallel with each other and none are in series, but I've never seen anything...
  10. R

    Exploring Order of Elements in Groups: Part (a) & (b)

    Homework Statement [PLAIN]http://img541.imageshack.us/img541/9880/34132542.gif The Attempt at a Solution For part (a), I think since the order of an element g is the smallest integer n such that gn=e, we will have: 8n mod 65 = 1 => n=4 64n mod 65 = 1 => n=2 14n mod 65 =1 =>...
  11. O

    Issue regarding oxygen storage with other elements

    this is from Nick Lane's Oxygen book I didn't quite understand this paragraph regarding the sudden release of a large amount of oxygen from cyanobacteria following the ice ages i don't understand how it's better to bury it. surely reacting with organic matter would be better as it is...
  12. M

    Is it possible to separate the 3 elements in cloth Carbon,oxygen and Hydrogen

    is it possible to separate the 3 elements in cloth Carbon,oxygen and Hydrogen without wetting it? Gas? Sound waves? Making the elements heavier?
  13. L

    Do we know more sure that we have made all of the elements that we can possibly make

    On the table of elements chart it's known that many of the elements are man made? or at least a few of them? Curious, do we know more sure that we have made all of the elements that we can possibly make? Is that all the combinations of elements that can possibly exist? Is the theory valid...
  14. M

    Why and How Does the f-block elements differ in e.config. from aufbau principle

    Hi all I cannot understand Why Does the f-block elements differ in their electronic configuration from aufbau principle... Please I want to understand this particular mystery.. thanx
  15. QuarkCharmer

    Principia v. Euclid's Elements

    I'm looking to start working through one of these books. I don't read latin, so clearly it would have to be translated. There are so many editions of these works that I am having a really difficult time deciding which to get. The amazon.com reviews for all of them are good. I hope this is...
  16. P

    Why We Have Heavy Elements on Earth

    Why we have (although very little) on Earth heavy elemnents such as uranium, lead, ... if they weren't created in Big Bang or stellar nucleosynthesis (these proceses don't produce elements heavier than iron and nickel). Any guesses?
  17. U

    Set M of all elements not in M

    Is this set a variation of Russell's paradox? M = \{x : x \notin M \} I understand this formulation a lot more than R = \{S : S \notin S\} because I don't understand how, for example, 1 is a member of itself. Is 1 a set? Are all numbers sets?
  18. M

    Silly question about matrices with matrix elements

    Doing some quantum mechanics, I just ran into the notion of a matrix whose elements have matrix values for the first time. Specifically, a 2x2 matrix whose elements are 4x4 matrices. This got me wondering how I can extend the question into the absurd. I can't think of any good reason that...
  19. R

    Mutual Inductance of two current elements

    I've been working my way through an old scientific paper on inductance calculation, and there's a fundamental principle I'm having a problem with. Suppose there are two filamentary conductors of any arbitrary shape. Now consider an infinitesimal element dl1 somewhere on the first conductor...
  20. J

    Greek classical elements, plato, his five solids

    Statement: The ancient Greek philosopher Plato theorized that the http://en.wikipedia.org/wiki/Classical_element#Classical_elements_in_Greece". I'm not a philosophy or science student, so please keep your reply plain and straightforward. Thanks. I can understand the literal meaning of the...
  21. Y

    Z bosons from radioactive elements?

    So I heard a little rumor that Beta decays in certain isotopes release an electron at "ultrarelativistic" speeds. I also heard a rumor that Z bosons can be created temporarily by a positron annihilating an electron when the two collide. My question is, can one place two highly...
  22. P

    Kronecker product on only a few elements in a matrix: How to align resulting elements

    The Kronecker product of an argument X and a 2x2 matrix, increases the dimensions of each argument X individually. If each argument X is a scalar value, it now becomes a 2x2 matrix. How are these arguments now aligned with each other and the other elements in the resultant matrix? For...
  23. S

    Counting Subsets of A with k Elements and Sum of r

    Dear Friends, I have a question and would be pleased if you help me by suggesting a paper or book to study. Let A={1,2,...,n}. We consider all the subsets with k elements. How many of these sets have a sum of r ? e.g. for n=6, k=3, r=10 {1,3,6} {1,4,5} {2,3,5} Hense the...
  24. N

    Sum of n elements of a finite set of integers, 1 through s

    The general problem I'm trying to solve is the probability of rolling a total t on n s-sided dice. A good chunk of the problem is easy enough, but where I run into difficulty is this: How many combinations of dice will yield a sum total of t? Because the number set is limited, {a \choose n-1}...
  25. A

    Finding Ricci Scalar Constant Nonzero Line Elements

    i need examplees where the ricci scalar is constant but nonzero . Particulary i search examples of line element. Pd: this is not a homework,
  26. Philosophaie

    Working with Keplerian Elements & Deriving Vernal Equinox

    I am working with the Keplerian Elements from the JPL web site. a - Semi-Major Axis e - Eccentricity I - Incilination L - Mean Longitude long.peri. - Longitude of the Periapsis long.node.or N - Longitude of the Ascending Node http://ssd.jpl.nasa.gov/txt/p_elem_t2.txt From this...
  27. Z

    Chemistry Finding mole and name of elements

    Homework Statement a sample of 0.6 moles of a metal M reacts completely with excess of flourine to form 46.8 gms of MF2. a)how many moles of F are present in the sample of MF2 that forms? b)which element is represented by the symbol M? Homework Equations NO. OF MOLES=given mass/molar...
  28. M

    Newmark's method to solve a system of spring elements

    Hi, I have been trying to solve a system consisting of 3 linear spring elements using the Newmark's method to find displacement, velocity and acceleration in Matlab. I followed the instructions shown on page 5 of the paper attached and my code does not seem to be working as the displacement...
  29. B

    Ansys Workbench Commands (Cable type elements)

    I am doing a nonlinear analysis in, Ansys Workbench, of a fuel tank tied down in an aircraft using cargo straps. I need to know how to insert a command function in Ansys workbench 11 that creates compression only elements (in order to model cargo straps). Based upon what have been reading I...
  30. M

    Retrieving Indices of a vector whose elements fulfil a criteria

    I have a 100x1 vector A, and want to know the ten indices i for which A(i) are the greatest 10 values in A. I can find the values by: B = sort(A) B(1:10); But I don't know how to find the indices, apart from starting a new if loop which searches the entire matrix (which seems very time...
  31. J

    Celestial Mechanics: Osculating Orbital Elements using Gass' Variational Equations

    Homework Statement The orbital elements (a,e,i,w,Omega,f) are to be integrated forward in time using two methods: 1) Cowell's method, which is direct interation, and 2) Gauss' Variational diffeential equations. The full assignment description, initial conditions, and my code are given in the...
  32. M

    What is exact reason behind choosing basic primitive shapes for elements in FEA?

    what is exact reason behind choosing basic primitive shapes for elements in FEA? Why it can't be hexagonal, pentagonal, octagonal, etc. in both cases 2D and 3D... Thanks in advance...
  33. D

    Mathematical notation to multiply matrix elements

    Hi all, I need to figure out the mathematical notation to multiply matricies A and B = C so that... If matrix A is... a1 a2 a3 a4 a5 and matrix B is... b1 b2 b3 b4 b5 so that matric C is... a1*b1 a2*b2 a3*b3 a4*b4 a5*b5 Would this involve using a the transverse of a...
  34. F

    ANSYS workbench - finer elements gives errous results

    Hello! I'm doing a simulation in ansys workbench mechanical (12.1) of a cantilever beam (axle) fixed to a wall and loaded radialy at the other end. The funny thing here is that when the mesh is rather coarse the results regarding von-mises stress (at the support where the bending moment is...
  35. K

    P-groups and orders of elements

    Homework Statement Let p be a prime and let H be a group of order p^n, some n > 0. Prove that for any x not equal to 1 in H, some power of x has order p. Homework Equations -- The Attempt at a Solution I know that by lagrange, for any x in G, if x is not the identity, then x has an order p^r...
  36. W

    Subgroups and prime order elements

    The question: Let n > 1 be a fixed integer and let G be a group. If the set H = {x in G : |x| = n} together with the identity forms a subgroup of G, what can be said about n? I know that n must be prime, but I can't figure out why that would be. The elements of h only have order 1 or n...
  37. S

    Defining Elements on the Real Line?

    RE-EDIT: I'm confused again, continue on reading :redface:Bonjourno, I'm trying to work at the lectures provided on youtube by nptelhrd but I've gotten my foot stuck in a hole in the real line only 15 minutres into it :frown: (In my head I say "such that" whenever the symbol : pops up!). We...
  38. W

    Centralizers and elements of odd order

    I was going over a proof in which the following is given: if abb=bba and b is of odd order, then ab=ba (i.e. if b^2 centralizes a then so does b) I'm not sure why this is so. Any clarification would be appreciated. Cheers, W. =)
  39. G

    How to find the elements of a subgroup?

    If you have a subgroup and it's order how do you find the elements of the group? I'd be happy with any example to help explain this, but just so there's something to go off of my example would be if you have a subgroup A4 = <(1 2 3), (1 2)(3 4)> of S4 that has an order of 12 how do you find...
  40. N

    Matrix Elements: J_+*J_- = J^2 - J_z^2+hbarJ_z?

    Well, \langle j,m|S^2_{-}|j,m\rangle=\langle j,m|(S^2_{-}|j,m\rangle) and S^2_{-}|j,m\rangle=S_{-}(S_{-}|j,m\rangle)=___? Normally J_+*J_- is substituted as J^2 - J_z^2+hbarJ_z As described above, J_+(J_-J_+), wouldn't the content in parenthesese just cancel out to 1 ?
  41. J

    Hardness vs. density (for Elements)

    I heard someone suggest a correlation between the two, my guess is NO direct correlation exists. Pick an Element on the periodic table, hardness and density do not always correlate. I'm sure atomic lattace structure plays a larger role here. Diamond is the hardest, but by no means high in...
  42. H

    Matrix Elements of x^3 Perturbation Theory

    Homework Statement I'm working on problem 3 on page 136 in Landau and Lifgarbagez Quantum mechanics nonrelativistic theory. The problem is to determine the energy levels of an anharmonic linear oscillator with H=H0 + a*x3 + b*x4 (where H0 is the hamiltonian of the harmonic oscillator)...
  43. R

    Mixing all 94 naturally occuring elements together at once.

    What if you had a large and very hot sphere (made of a a thick alloy/material with a higher melting point than any of the elements) and you fired in the 94 natural elements to collide in equal parts in the center and make a ball that fits the sphere? The solid elements would be in a powdered...
  44. L

    Is Evaporation a Physical or Chemical Change?

    Hello everyone I was wondering if someone can check out my answers thanks! 1. A cotton ball is dipped in alcohol and wiped across a tabletop. Explain what happens to the alcohol molecule deposited on the tabletop. Is this a physical or chemical change? The alcohol molecule evaporates...
  45. M

    Is A^2 equivalent to AxA or all the elements of A are squared?

    Homework Statement I was just wondering if say A is a 2x2 matrix. Is A^2 equivalent to AxA or all the elements of A are squared? Homework Equations let A and B be 2x2 matrices. is the following true? (A-B)(A+B) = A^2 - B^2 The Attempt at a Solution
  46. P

    Artificial elements. whats the point?

    Hi everybody. Can I just start off by saying how much I enjoy reading all your posts and trying to increase my scientific knowledge. But now its time for me to ask my own questions. I've just finished watching a programme about elements and was wondering. 1.what use do we have of some of the new...
  47. P

    Star generatations making elements

    How many generations of stars were required to make the elements found on Earth. In other words, does a star have to be born with heavier elements for some even heavier elements to form?
  48. T

    Binomial Theorem & Nilpotent Elements in a Ring: Is (a+b)m+n Nilpotent?

    I have this question and its a combination of the binomial theorem and nilpotent elements within a ring. Suppose the following, am=bn=0. Is it necessarily true that (a+b)m+n is nilpotent. For this question I did the following: \sumi=0m+n\binom{m+n}{i}am+n-ibi If i=m, then a=0...
  49. L

    Predicting Compound Formulas from Group 7 & Group 1 Elements

    Homework Statement Hello, could you please explain to me in simple terms how I can predict the chemical formula of the compounds produced when Group 7 elements are reacted with the elements in Group 1. Thanks. Homework Equations N/A The Attempt at a Solution N/A
  50. E

    Efficient Enumeration of Elements in a Group Defined by Generators

    Here is my problem: i have group defined by generators, like: < a, b | a^2 = b^3 = (ab)^5 = 1 >. eg. from http://for.mat.bham.ac.uk/atlas/v2.0/alt/A5/ i can't find algorithm to enumerate all element of group ( 60 in this example ) based on generators. thanks for any help :)
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