Measure Definition and 1000 Threads

  1. Math Amateur

    I Translation Invariance of Outer Measure .... Axler, Result 2.7 ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 2: Measures ... I need help with the proof of Result 2.7 ... Result 2.7 and its proof read as follows: In the above proof by Axler we read the following: " ... ... Thus ... ##\mid t +...
  2. Math Amateur

    MHB Translation Invariance of Outer Measure .... Axler, Result 2.7 ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 2: Measures ... I need help with the proof of Result 2.7 ... Result 2.7 and its proof read as follows: In the above proof by Axler we read the following: " ... ... Thus ... $\mid t + A...
  3. Math Amateur

    I Lebesgue Outer Measure .... Carothers, Proposition 16.2 (i) ....

    I am reading N. L. Carothers' book: "Real Analysis". ... ... I am focused on Chapter 16: Lebesgue Measure ... ... I need help with the proof of Proposition 16.2 part (i) ... Proposition 16.2 and its proof read as follows: Carothers does not prove Proposition 16.2 (i) above ... Although it...
  4. Math Amateur

    MHB Lebesgue Outer Measure .... Carothers, Proposition 16.2 (i) ....

    I am reading N. L. Carothers' book: "Real Analysis". ... ... I am focused on Chapter 16: Lebesgue Measure ... ... I need help with the proof of Proposition 16.2 part (i) ... Proposition 16.2 and its proof read as follows: Carothers does not prove Proposition 16.2 (i) above ... Although it...
  5. Math Amateur

    MHB Lebesgue Outer Measure .... Carothers, Proposition 16.1 ....

    I am reading N. L. Carothers' book: "Real Analysis". ... ... I am focused on Chapter 16: Lebesgue Measure ... ... I need help with an aspect of the proof of Proposition 16.1 ... Proposition 16.1 and its proof read as follows: In the above text from Carothers we read the following: " ... ...
  6. Math Amateur

    MHB Lebesgue Outer Measure .... Carothers, Proposition 16.1 ....

    I am reading N. L. Carothers' book: "Real Analysis". ... ... I am focused on Chapter 16: Lebesgue Measure ... ... I need help with an aspect of the proof of Proposition 16.1 ... Proposition 16.1 and its proof read as follows: In the above text from Carothers we read the following: " ... ...
  7. Math Amateur

    I Lebesgue Outer Measure .... Carothers, Proposition 16.1 ....

    I am reading N. L. Carothers' book: "Real Analysis". ... ... I am focused on Chapter 16: Lebesgue Measure ... ... I need help with an aspect of the proof of Proposition 16.1 ... Proposition 16.1 and its proof read as follows: In the above text from Carothers we read the following: " ... ...
  8. Math Amateur

    MHB Outer measure of an open interval ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 2: Measures ... I need help with proving that the outer measure of an open interval, \mid (a, b) \mid = b - a Axler's definitions of length and outer measure are as follows: Can someone...
  9. Math Amateur

    MHB Outer measure .... Axler, Result 2.14 .... Another Question ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 2: Measures ... I need further help with the proof of Result 2.14 ... Result 2.14 and its proof read as followsIn the above proof by Axler we read the following: " ... ... To get started...
  10. Math Amateur

    I Outer measure .... Axler, Result 2.14 .... Another Question ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 2: Measures ... I need further help with the proof of Result 2.14 ... Result 2.14 and its proof read as follows In the above proof by Axler we read the following: " ... ... To get...
  11. Math Amateur

    I Outer measure of a closed interval .... Axler, Result 2.14 ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 2: Measures ... I need help with the proof of Result 2.14 ... Result 2.14 and its proof read as follows: In the above proof by Axler we read the following: " ... ... We will now prove by...
  12. Math Amateur

    MHB Outer measure of a closed interval .... Axler, Result 2.14 ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 2: Measures ... I need help with the proof of Result 2.14 ... Result 2.14 and its proof read as follows: In the above proof by Axler we read the following: " ... ... We will now prove by...
  13. Math Amateur

    MHB Outer Measure .... Axler, Result 2.5 ....

    I am reading Sheldon Axler's book: Measure, Integration & Real Analysis ... and I am focused on Chapter 1: Measures ... I need help with the proof of Result 2.5 ... Result 2.5 and its proof read as follows: Now \mid A \mid \leq \sum_{ k = 1 }^{ \infty } l(I_k) follows from Axler's...
  14. danielhaish

    Is it possible to measure the general amount of electromagnetic field

    We relating to an electromagnetic radiation as waves. and in waves there is maximum point and minimum point but when there is permanent electromagnetic level there is no disorder or weave . so is it possible to measure it in blank space relative to other places
  15. Amitkumarr

    To measure the diameter of a sphere using a screw gauge

    Least count of the screw gauge = Pitch÷No. of divisions on circular scale=1.5÷100 mm =0.015mm According to me,in this case the main scale reading should be taken as 2 mm because it is the one which is visible and circular scale reading should be 76. So, Diameter=2 mm + 0.015×76 mm = 2 mm + 1.14...
  16. A

    I How to measure a 21 cm EM wave if it is Doppler shifted?

    we know that all emission from asctrophysical context is doppler shifted. So, how to make sure the doppler shifted 21 cm not contaminated by some other emission?
  17. F

    Which sigma algebra is this function a measure of?

    Suppose ##\nu## is a measure on some ##\sigma##-algebra ##\mathcal{A}##. Then we must have for all ##A \in \mathcal{A}## either ##A## or ##A^c## is finite, but not both. Because otherwise ##\nu(A)## is undefined or not well defined. I've verified that ##\lbrace \emptyset, X \rbrace## and...
  18. F

    Can a Pre-Measure on a Symmetric Sigma Algebra Be Extended to Borel Sets?

    Attempt at solution: We have ##\sum = \lbrace B \subset \mathbb{R} : b \in B \Rightarrow -b \in B \rbrace##. Clearly, ##\emptyset \in \sum##. Let ##B \in \sum## and ##a \in B^c##. Then ##a \not\in B## which implies ##-a\not\in B##. So ##-a \in B^c## i.e. ##B^c \in \sum##. Lastly, for any...
  19. L

    A Concurrence as a measure of entanglement

    In book Quantum computing explained by David Mahon concurrence, as a measure of entanglement is defined as C(\psi)=|\langle \psi|\tilde{\psi} \rangle | where ##|\psi\rangle=Y \otimes Y|\psi^*\rangle## or with density matrix ##\rho(Y \otimes Y)\rho^{\dagger}(Y \otimes Y)##. Could someone explain...
  20. dRic2

    How to measure the activity of a radioactive source

    Hi, I've been reading about radiation detectors (manly form Knoll's book), but there is something I don't understand. Radiation detectors are of very different nature, but they all share a common process to detect a type of radiation: - I have a control volume - The incoming radiation interacts...
  21. A

    Temperature is a measure of the average kinetic energy of a gas?

    Why do they say temperature is a measure of average kinetic energy how is this possible. how can we take it is it applicable for all types of gases?
  22. LCSphysicist

    Kleppner 7.10 — Using a gyroscope to measure latitude

    I am not sure about a, but i think as long as there is no torque about the Lp direction, it will remain constant with relation to the polar star. I would like help in proof this mathematically. I just don't know how to proceed, i wonder if i would need to consider the torque provide by...
  23. E

    Create a method to measure a varying voltage from a power line

    I feel like i am spinning my wheels at the start here. so I figured that i would start with some type of wire loop that I could change its diameter. This would allow there to be a change in flux through the loop creating a current through the wire. i could then read the current through the...
  24. MathematicalPhysicist

    I Measure zero (a possible problem in the reasoning)

    I read the proof here: https://proofwiki.org/wiki/Measure_of_Empty_Set_is_Zero that the measure of the empty set is zero.
  25. SEYED2001

    B Can we measure any two of the energy, momentum or mass simultaneously?

    I want to know between which two quantities of energy, momentum, and mass there is an uncertainty principle going on. Can I measure any two of those at the same time? If yes, which ones? Thank you in advance
  26. rtx22

    How can I measure the terrestrial tide on my place?

    How can I measure the terrestrial tide on my place? Since i don't have a MEMS gravimeter or a laser spectometer what will be the simplest method to measure the local Earth tide variations?
  27. X

    Measure flow rate with a manometer (pressure gauge)

    Hello! I have a volume of 50 liters which I pressurize with air so that I read 1 bar on the manometer. But there is a leakage in the volume so after 30 sec the manometer shows 0,5 bar. What is then the air flow ( liter / min) of the leakage?
  28. hugo_faurand

    How to measure a quantity of grains for an instant coffee maker project?

    Hello everyone ! I have to built a coffee machine with a coffee tank (instant coffee) and a sugar tank. I'd like to measure a certain quantity of those grains. First, I wanted to make a physical model to know the debit of the grains. But I noticed that it depends on many things like the...
  29. M

    How to Measure Impact Force / Energy Absorption

    Hi, I am a bit out of my league here, but had a question. I have 5 pieces of .25" thick foam/padding of different densities, and I wanted to measure which one absorbs the most energy (weakens the impact) when struck by a fist/punch or even a ball, how would I do that? I ran across a...
  30. areamer02

    How do peak flow meters measure flow rate?

    I am in pharmacy school and my professor recently went over lung diseases with us. An important (and cheap) tool that many patients can use to detect whether their lung function is declining is a peak flow meter, which tells the patient how much air they are moving when they exhale with as much...
  31. SapientiaPT

    An experiment to measure the Speed of Light

    So, pretty much I want to make an experiment in order to get the speed of light. What I plan to do is to have a lantern in the dark(initially off) perpendicular to a wall, two sensors(one closest to the lantern and the other closest to the wall), then turn on the light making sensor 1 go off as...
  32. D

    How Can You Narrow Possibilities When Measuring Inductor Back EMF?

    i am planning to measure the back emf produced by inductor when you open a switch. i know it is very hard to predict the voltage. but is there any way to narrow the possibilities?
  33. T

    Wave motion and two detectors to measure that motion

    Solving for t' by substitution I obtained t' = 7/8. Then I substituted x= 10 and t = 7/8 in the given equation. Is that the right way to do it? My answer key says the answer is 100 but I am getting 78.5.
  34. Sonim

    Can Calorimeters Measure Enthalpy Variation of Fast Reactions?

    First of all this is a question that I had while reading some concepts of my book, so this isn't a homework question. I have started reading the thermochemistry chapter of my book, and it shows the story of Hess' Law and says that it was created is because a calorimeter can't be used to measure...
  35. AlexVY

    Ways to measure elastomer swell

    Summary: Cost-effective ways to measure the swell of elastomers of submersible pumps after they are pulled from wells Dear Physics Community! I am working for an energy company and we are using progressive cavity pumps (PCPs) for producing water from our wells. This is a youtube video...
  36. H

    I Any direct measure of Universe expansion via galaxy subtended angles?

    As indicated in the title and summary, I'm wondering if there is any large scale astronomical effort to assess directly the universal spatial expansion assumed by the Doppler interpretation of the redshift/distance relationship, by measuring individual galaxy subtended angles over time. The...
  37. S

    How to measure electric and magnetic fields in asymmetric capacitors?

    Summary: I need to build an asymmetric capacitor, but the mathematics of electromagnetics become too tough, do you have any info that can help? Appreciate it! Hello, I am an undergraduate student in engineering and I want to build an asymmetric capacitor, so I need electromagnetics which I...
  38. Durianpastry

    How to measure the bandwidth of a photodetector?

    I am new to photodetectors. I know there are usually two concepts of bandwidths of photodetectors, i.e the spectral and electrical. What I do not understand is the electrical bandwidth. The electrical bandwidth is used to calculate the shot noise of a photodetector. However, the papers usually...
  39. I

    Sound waves carrying mass and how to measure it

    I don't know in which category this subject belongs to. Anyways, here it is: https://www.sciencealert.com/a-new-study-backs-up-claims-that-sound-waves-really-do-have-mass-after-all?fbclid=IwAR2Cmsxm_Garm0PVn03f4UxVQ8adcK4Il3A_N7bUbJT1KaGR1ZfCbGuWVLE How exactly is this measured? Can we expect...
  40. M

    Sensor to Measure Differences in Light Wavelength

    What sensor to would i use to measure the difference in wave length periods. I want to make a rendered image of somthing that field of view that is being obstructed.
  41. C

    I How to measure ion energy in a plasma?

    I was looking at things today and read (on wiki) that the use of Thompson Scattering reveals electron temperature in a plasma, not ion temperature. I thought that's how ion temp was measured (or maybe it is and the wiki text was incomplete)? Could someone please clarify how ion temperatures in...
  42. L

    A Definitions of Cylinder Sets and Cylinder Set Measure

    I'm trying to learn about Abstract Wiener Spaces and Gaussian Measures in a general context. For that I'm reading the paper Abstract Wiener Spaces by Leonard Gross, which seems to be where these things were first presented. Now, I'm having a hard time to grasp the idea/motivation behind the...
  43. mPlummers

    Relative error and measurement precision

    NOTE: this is a programming exercise (Python). I started adding to ##x_{true}## an error related to a (for example) 10% relative error, obtaining ##x_{measurement}##. Then i computed ##y_{measurement}##. To find the precision, i calculated ##(y_{true}-y_{measurement})/y_{measurement}##. If it is...
  44. DariusP

    How does a laser rangefinder measure distances up to 20 km?

    Hello, I've known about average laser rangefinders that we can use for domestic needs. They're relatively cheap and can measure up to 50 meters but that's about it. However, I've read that military laser rangefinders are able to measure distances using light up to 20 kilometers. How is that...
  45. H

    Is Tonelli's Theorem a Useful Tool for Determining the Existence of Integrals?

    Hi I am sitting with a homework problem which is to show if I can actually integrate a function. with 2D measure of lebesgue. the function is given by ##\frac{x-y}{(x+y)^2} d \lambda^2 (x,y)##. I know that a function ##f## is integrable if ##f \in L^{1}(\mu) \iff \int |f|^{1} d \mu < \infty##...
  46. Ismael Jarada

    How to measure the torque of a compressed air engine?

    Summary: The main idea of my graduation project is to convert the motorcycle engine to work on compressed air that come from a 180 L tank (10 bar compressed air inside the tank ) I have some problems to how calculate the required torque to move the cart . The main idea of my graduation project...
  47. P

    Predicting tsunamis, what to measure from earthquake data?

    I have a project to create a program to predict tsunami possibility by gathering data and finding pattern from previous earthquakes. It would be using neural network. But I don't really know what I should consider from the data. Is it the magnitude that cause the tsunami? Or is it the depth...
  48. L

    Measure the torque of a servo motor

    I have a servo motor which rotates 180 degrees. I want to calculate torque of the motor. To calculate the torque I'm thinking of lifting a load of a known value, with a known angular velocity. But I am struggling to find/calculate the torque based on these values. Does anyone know how to do this...
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