What is Local: Definition and 519 Discussions

Local history is the study of history in a geographically local context and it often concentrates on the local community. It incorporates cultural and social aspects of history. Local history is not merely national history writ small but a study of past events in a given geographical but one that is based on a wide variety of documentary evidence and placed in a comparative context that is both regional and national. Historic plaques are one form of documentation of significant occurrences in the past and oral histories are another.
Local history is often documented by local historical societies or groups that form to preserve a local historic building or other historic site. Many works of local history are compiled by amateur historians working independently or archivists employed by various organizations. An important aspect of local history is the publication and cataloguing of documents preserved in local or national records which relate to particular areas.
In a number of countries a broader concept of local lore is known, which is a comprehensive study of everything pertaining to a certain locality: history, ethnography, geography, natural history, etc.

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  1. T

    What is the meaning of the local gauge transformation exactly?

    What is the meaning of the local gauge transformation exactly?? These days I'm studying. [D.J. Griffiths, Introduction to Elementary Particles 2nd Edition, Chapter 10. Gauge Theories] Here the Section 3. Local Gauge Invariance, the author gives the Dirac Lagrangian, \mathcal{L}=i \hbar c...
  2. Z

    How Many Local Maxima Does F(x) = (sin(Nx)^2)/(sin(x)^2) Have?

    1. Show that the function F(x)=(sin(Nx)^2)/(sin(x)^2) has N-2 local maxima in the interval 0<x<pi Homework Equations 3. I am stuck after i have calculated the derivate, (2Nsin(Nx)cos(Nx)sin(x)^2-2sin(x)cos(x)sin(Nx)^2)/sin(x)^4 = 0 I am not sure how to simplify this equation, so...
  3. B

    Local Trivialization in Covering Spaces

    Hi, All: I am trying to understand why covering maps have the local triviality condition, i.e., given a cover C:X-->Y, every point y in Y has a neighborhood Oy of y with p^-1(Oy)~ Oy x F, where F is the fiber. This seems confusing, in that fibers of covering maps are a (discrete)...
  4. H

    Problem running 220volt motor on local electricity supply

    The local electric supply in our country is 415 volts. Our company recently imported plant and machinery. All the motors and electric panels that have been imported are on 220/110 volts specifications. The total load of the motors is 110 Kw. The motors are now tripping as soon as they are...
  5. M

    Getting from (3D gravity + local degrees of freedom) to 4D gravity

    Haelfix pointed out the paper http://arxiv.org/abs/1105.4733" , and Witten 2007 (discussed in that thread) expresses doubt that 4D gravity could be exactly solved, precisely because it has local excitations. And yet here Maloney et al have done it in 3 dimensions. Can something about their...
  6. L

    (Fluids) Material and local velocity and acceleration fields.

    Homework Statement The streamlines of a fluid are as follows: x = (x0) + 3(y0)t^2 y = (y0)/(1 + 2t) z = (z0) + 5(x0)t Find the velocity and acceleration fields in the Eulerian description (local). Homework Equations Total/material acceleration: Dv/Dt = dv/dt + v.grad(v) The...
  7. K

    Local SU(2) Gauge Transformations

    Hi all, (Also - if anybody could tell me how to get the latex to work on this page that'd be very handy!) While not technically homework this is a problem I've found I'm stuck on during my revision. Any help would be greatly appreciated. Homework Statement "By demanding that the covariant...
  8. L

    Local Coordinates for Non-Uniformly Accelerated Observer

    Hi, I'm reading a paper about acceleration and the author states the local coordinates of the observer (\tau,x) (for a non-uniformly accelerated observer) are specified (in relation to the inertial coordates (T,X))...
  9. B

    Complex Analytic Bijection: Is it a Local Diffeo?

    Hi, Everyone: Say f(z) defined on a region R , is a complex-analytic bijection. Does it follow that f:R--->f(R) is a diffeomorphism, i.e., is f<sup>-1</sup> also analytic? I know this is not true for the real-analytic case, e.g., f(x)=x<sup>3</sup> , but complex- analytic...
  10. R

    Local and convected rates of change

    Homework Statement This is less of a help me answer something question more a help me understand this question. I was reading though my hydrodynamics notes and there was a derivation that ended up with the follow equation \frac{D\psi}{Dt} = \frac{\partial\psi}{\partial{t}} +...
  11. O

    Local Extrema with Partial d/dx

    Hello, I'm been stuck on this problem and I've been staring blankly at it way too long. I stumbled upon here and thought I'd ask for help? :P Alright well, I'm looking for a local max/min, and I've already done the first partials and I got *f(x)=2x-y and f(y)=-x+2y+6; I'm sure those are right...
  12. A

    Local to global transformation; end rotational displacments

    Hi I am analysing some piping which starts off as being aligned with the global axis system (X Y Z). So axially its X, laterally is Y and Z is vertically upwards. Due to bends etc. the end of the pipe is in a different orientation though still in the same plane - now the local axis system is x...
  13. R

    Lorentz Invariance as local limit of Bigger Manifold

    Is it possible that Lorentz invariance is just a lower limit of a larger manifold that has a priveleged frame? Even if Bell's experiments can't transmit signal faster than light. The spirit of relativity is still violated by say instantaneous correlation between 10 billion light years. As...
  14. M

    The Efficiency Loophole: A Local Hidden Variables Theory?

    If we assume that an electron in an entangled pair has more than 2 plans (plans that determine if an electron go up or down through a magnet) to choose from, can we create a local hidden variable theory? If this is true, how many plans to choose from would an electron need for this to work...
  15. H

    Finding Values given only local max and min.

    Homework Statement Find the values of a and b if the function f(x) = 2x3 + ax2 + bx + 36 has a local maximum when x = −4 and a local minimum when x = 5. Homework Equations I'm not even sure how to start this, it's just baffling me for some reason The Attempt at a Solution i do...
  16. A

    Exact meaning of a local base at zero in a topological vector space

    I am confused as to exactly what a local base at zero (l.b.z.) tells us about a topology. The definition given in Rudin is the following: "An l.b.z. is a collection G of open sets containing zero such that if O is any open set containing zero, there is an element of G contained in O". Ok, great...
  17. G

    Help drawing a function, finding its zero, local max/min

    Hello to all. I'm having a few problems and would love to know how to do the following. 1. f(x) = 3x^2-8 2. Find the function's zeros, local max/min and the function's behaviour 3. My attempt at drawing the function ended with a downward curve intercepting at y=-8, x=0 But a...
  18. B

    Prove that the gradient is zero at a local minimum.

    Homework Statement Suppose F: Rn --> R has first order partial derivatives and that x in Rn is a local minimizer of F, that is, there exists an r>0 such that f(x+h) \geq f(x) if dist(x, x+h) < r. Prove that \nabla f(x)=0. Homework Equations We want to show that fxi(x) =0 for i = 1,...,n So...
  19. M

    Sun Local Hour Angle and Latitude

    Homework Statement if: H = Local Hour Angle Lat = Latitude. Dec = Sun Declination. cos(H) = -sin(a)-sin(Lat)*sin(Dec) / cos(Lat)*cos(Dec) I wand to get The value of Lat . The Attempt at a Solution I Tried to make it simple By : 1 - multiply both sides by the denominator 1-...
  20. J

    Density Functional Theory and the Local Density Approximation

    Im trying to calculate the ground state energy of Helium using a density functional theory approach combined with the local density approximation. So far I have set up universal functionals and I mainly need help with the actual algorithm the evaluation of the Hartree energy functional.
  21. G

    What's wrong with this local realistic counter-example to Bell's theorem?

    This thread is an offshoot of https://www.physicsforums.com/showthread.php?t=403210 -- Joy Christian's disproof of Bell. This thread is a response to: THE SAKURAI LINK (above) SHOULD BE STUDIED AND UNDERSTOOD. This thread also has its basis in the following [somewhat edited] exchange: So the...
  22. D

    Coordinate System Rotation Matrix (global to local)

    I feel I may have improperly posted this thread https://www.physicsforums.com/showthread.php?t=469331" but am just not as knowledgeable in my matrix math as I need to be. One (me) would think that somehow you should be able to get a rotation matrix from these two systems. Homework Statement So...
  23. pellman

    Coordinate basis vs local frame?

    The wikipedia article on connection forms refers to a local frame. What is the relationship between local frames and coordinate bases? Are they the same thing? Is one a subset of the other? The connection form article uses general notation e_\alpha for the basis elements instead of the...
  24. R

    Optimization problem, local minima and feasible set

    Homework Statement minimiza f(x) = x_1 subject to (x-1)^2+y^2=1 (x+1)^2+y^2=1 Graph the feasible set, Are there any local minimizers and global minimizers? Homework Equations I have graphed the feasible set...
  25. G

    Local or Nonlocal Physics: The Concept of "Fields" vs. "Entanglement

    The concept of “fields” told us that our physics is local, while the concept of "entanglement" seems to say that there is something nonlocal So I wonder whether our physics laws are local?
  26. B

    Local effects of universal expansion

    First let me apologize for asking these questions. So much has been devoted to discussing the expansion of space both on the internet in general and this forum that the answers to my question are probably out there, but there is a lot to wade through. A lot. I found this forum and thought...
  27. haushofer

    Vielbeins as gauge fields of local translations

    Hi, I have a question about gravity. I think most of you know that we can obtain Einstein gravity by gauging the Poincaré algebra and imposing constraints. The Poincaré algebra consists of {P,M}. P describes translations, and M describes Lorentz rotations. Gauging M gives us the so-called...
  28. radou

    Uniform topology and local finiteness

    Homework Statement For some reason, the uniform topology always causes me problems. So, let's work this through. Let Rω be given the uniform topology, i.e. the topology induced by the uniform metric, which is defined with d(x, y) = sup{min{|xi - yi|, 1}, i is in ω}. Given some n, let...
  29. Y

    Local deterministic model of singlet state correlations

    Phys. Rev. Lett. 105, 250404 (2010) Local deterministic model of singlet state correlations. The derivation of Bell inequalities requires an assumption of measurement independence, related to the amount of free will experimenters have in choosing measurement settings. Violation of these...
  30. O

    How i find the Local minimum or Maximum Of the Function

    [(there is an option that there is no Local minimum or Maximum point in this Function) BUT i need to show the way. thanks.
  31. W

    Finding local maximums and minimums

    Homework Statement Find a cubic function g(x)=ax^3 +bx^2 +cx +d that has a local maximum value of 2 at -9, and a local minimum value of -7 at 8. Homework Equations The Attempt at a Solution I thought i would find the derivative and set it equal to zero, but i do not know what to...
  32. radou

    What is the Local Compactness of [0, 1]ω in the Uniform Topology?

    Homework Statement This one has been bothering me for a while. One needs to show that [0, 1]ω is not compact in the uniform topology. The Attempt at a Solution As a reminder, the uniform topology on Rω is induced by the uniform metric, which is defined with d(x, y) = sup{min{|xi -...
  33. W

    Can I use local variables from one method in another method?

    Without adding new Fields, how do I use local variables from another method in the same class? I know I could simply add these variables to the list of Fields and get to them that way but our instructor specifically told us NOT to do this. I am stumped. Heres the realavent code, in bold are the...
  34. K

    Local Minkowski space and free falling

    Einstein's equivalence principle states that free-falling observers are in local inertial frame, so one can construct a local Minkowski frame everywhere. So my question is whether the logic can be inversed, does every local Minkowski space represent free-falling? because in vierbein...
  35. W

    Finding local min, max, and saddle points in multivariable calculus

    Homework Statement Find the local maximum and minimum values and saddle point(s) of the function. f(x,y) = 1 + 2xy - x^2 - y^2 Homework Equations The Second Derivative Test: let D = D(a,b) = fxx(a,b)*fyy(a,b) - [fxy(a,b)]^2 if D > 0 and fxx(a,b) > 0, then f(a,b) is a local minimum...
  36. M

    Local Poincare Transformation

    Can any continuous coordinate transformation on a differential manifold be viewed as a poincare transformation locally in every tangent space of this manifold? Thx!
  37. radou

    A local path connectedness problem

    Homework Statement Let X be locally path connected. Show that every connected open set in X is path connected. The Attempt at a Solution Let U be a connected open subset of X. Since, X is path connected, for any x in X and any neighborhood N of X, there exists a path connected...
  38. andrewkirk

    Constructing a Valid Coordinate System for Local Flatness in General Relativity

    Hello all I am trying to teach myself general relativity and am working through the text 'a first course in general relativity' by Bernard F Schutz. So far I have made slow but consistent progress but I am perplexed by his derivation of the ‘local flatness’ result. This says that for any point...
  39. K

    Schools What's the admitance rate at your local university for math/physics/engineering?

    I live in ottawa and apparently University of Ottawa and Carleton University's admittance rates are both 75% for specialization in Math. Is is like that for most universities? This percentage holds true to physics as well. Engineers are more in the 80s.
  40. J

    Calculating uncertainty of local gravity

    Homework Statement My first lab report in physics requires me to calculate the value of local gravity. I did this using latitude and longitude. I must also state the uncertainty of my local gravity value. I have no clue how to do this. What am I basing my uncertainty on, and is there an...
  41. Rasalhague

    Local Lorentz Frame: Blandford & Thorne's Applications of Classical Physics

    Blandford & Thorne, Applications of Classical Physics: Taylor & Wheeler, Spacetime Physics: These definitions seem to be based on the notion of a "physical" or "practical" infinitesimal: a quantity too small to be detected. But how can we measure the accuracy of an imaginary detector...
  42. inflector

    Local Realistic in 4-Space Sliced to 3+1 Nonlocal

    I've been exploring an idea for reconciling the possibility of local realism with the various experimental proofs of violations of Bell's Inequalities. Since it seems like an idea that must have been explored and considered elsewhere, I am looking for relevant papers which have considered the...
  43. P

    Max Temperature Peak: Global vs Local Energy Source

    Ok, so say I have a system at a global temperature, I add an energy source (laser in this case) and it heats the system in a localized area. This leads to a maximum temperature peak in the system. Then you can get out a change in temperature from this maximum to the global. OK, now my...
  44. J

    Local lorentz tranformations of fermion action

    The action for a fermion in curved spacetime is S = -\int d^4 x \sqrt{- \det(\eta^{ab} e_{a\mu}e_{b\nu})} \left[ i\overline{\psi} e^\mu_a \gamma^a D_\mu \psi + i m \overline{\psi}\psi \right] where g_{\mu\nu} = \eta^{ab} e_{a\mu} e_{b\nu} and the derivative operator acting on fermions is...
  45. Pengwuino

    Is Local News Just About Weather and Elementary Schools?

    Local "news"? Sometimes I think all local news is for is telling us what the weather will be like and what's going on at elementary schools. So far I swear they went on for 5 minutes about how the air conditioning went off at an elementary school for 2 whole days! WHO CARES?!??! I'm just...
  46. N

    Can a theory have local Lorentz invariance but not diffeo invariance?

    This is related to the thread on the meaning of diffeomorphism invariance but is adressing a distinct point (at least I think so, but I may be proven wrong). As Rovelli discusses in his book, the action of the Standard Model coupled to gravity has three types of invariance: under the gauge...
  47. G

    Can partial vanishing of Poisson bracket determine local constants of motion?

    I don't know if this is the right place to post this, but my question is: if i have an Hamiltonian defined on the whole phase space and a function f which is also defined on the whole phase space and doesn't depend explicitly on time, i know that if its poisson bracket with the Hamiltonian...
  48. Simfish

    Is the conjugate gradient algorithm susceptible to getting into local minima?

    What about the nonlinear forms of it? Or is it guaranteed to reach a global minimum?
  49. K

    Local min/max/saddle points of 3d graphs

    Hello, just got done taking a test and one problem kinda confused me. Homework Statement f(x,y) = e^x cos y find local min/max and saddle points Homework Equations fx = e^x cos y fy = -e^x sin y The Attempt at a Solution I answered that there were no critical points for...
  50. Z

    Finding the Local Maxima of a Constant Function

    Does a constant function have a local maximum?
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