Definitions Definition and 263 Threads

Two metrics 'd' and 'f' are said to be equivalent on a metric space X, if they have the same set of open sets. This is equivalent to saying every open ball with respect to d contains an open ball with respect to f (different radius) and vice versa. (As every open set is a union of open balls)...

I'm trying to learn some analysis on my own, and as this is the first proof-based book I'm reading, I have a basic question about definitions I was hoping someone could help me with. For example, the book I'm reading says that: Given a subset of the real numbers A, b is an upper bound of A if...

I am using Axler's Linear Algebra Done Right as a text for independent study of linear algebra. Axler basically defined a vector space to be a set which has defined operations of addition and multiplication (and which comports with certain algebraic properties) and that contains an additive...

Homework Statement I\'m just trying to understand a definition: So for the clausius clapeyron equation, it really matters which way we define L (i.e. whether it is positive or negative), so trying to understand, is \"the latent heat of fusion of ice\" the same as \"the specific melting...

I'd like to test my understanding of some basic definitions using the example of a double coin toss. I think this would be formally modeled with the following structure: A1. The sample space, S = {(0,0),(0,1),(1,0),(1,1)}, whose elements (s1,s2) are called outcomes, where si = 1 means heads...

I'm really confused. I study physics, and in Relativity we deal a lot with vectors and tensors. I know an element x of Rn is a vector, because Rn is a vector space. That's fine. Now, in physics, we define a (contra-) vector xa (with 'a' an index running from 1 to n) as a n-tuple of quantities...

I'm really confused. I study physics, and in Relativity we deal a lot with vectors and tensors. I know an element x of Rn is a vector, because Rn is a vector space. That's fine. Now, in physics, we define a (contra-) vector xa (with 'a' an index running from 1 to n) as a n-tuple of...

Homework Statement dU = dQ + dW so dU = Cv dT... but only if dW is zero right? as dQ = CvdT so then the central equation is TdS = dU + PdV which is then TdS = CvdT + PdV according to my notes. surely PdV should be zero no?

There are a lot of definitions but what is the quickest way to see if a function is holomorphic? apply the cauchy riemann equations seems too slow. I thought if it doesn't have a z_bar in it, then it's automatically holomorphic. so for ex. polynomials are always holomorphic. on the other...

I'm trying to understand the proof of (ii)\Rightarrow(i) of proposition A.6.2.(1) here. The theorem says that the given definition of "locally compact" is equivalent to a simpler one when the space is Hausdorff. I found the proof quite hard to follow. After a few hours of frustration I'm down to...

srry if this post is in the wrong section but i was wondering if there are actually precise and universally agreeable definitions of the following terms of calculus. Different textbooks even give contrary definitions. Any help is appreciated thanks. increasing/decreasing = strictly...

Can someone please explain why the following three definitions for the norm of a bounded linear functional are equivalent? \| f \| = \sup_{0 < \|x\| < 1} \frac{|f(x)|}{\| x \|}, and \| f \| = \sup_{0 < \| x \| \leq 1} \frac{|f(x)|}{\| x \|}, and \| f \| = \sup_{\| x \| = 1}...

I'm wondering which of the following definitions of a flow is best. Is there one primary, rigorous, general definition of which the others are informal shorthands, or are the differences no more then superficial differences in convention? (1) Arnold, in Ordinary Differential Equations...

I'm reading Arnold: Ordinary Differential Equations, Chapter 1. In section 1.2, an integral curve was defined as the graph, in the extended phase space, \mathbb{R} \times M, of the motion \phi : \mathbb{R} \rightarrow M of a phase point in M. In 2.2, an integral curve is defined as the graph of...

https://www.physicsforums.com/showthread.php?t=466170 I'm currently trying to get better at math. I've decided to do research on every facet of mathematics, starting at the source: what is a number? And going from there, getting progressively more advanced. Instead of just trying to...

Homework Statement In quantum mechanics a physical observable is represented by an operator A. Define the terms eigenstate, eigenvalue and eigenfunction of a quantum mechanical operator. Homework Equations The Attempt at a Solution I think I know in that eq 'f' is the eigenfunction, and...

Meaning of "countable" in definitions of sigma algebra In the third axiom defining a \sigma-algebra, (X,\Sigma), does countable mean (a) "finite or countably infinite", or does it mean (b) "countably infinite".

Hey all, This might seem like a stupid question, and this might not be the correct forum, but hopefully someone can clarify it really easily. I often have seen two definitions of an inner product on a vector space. Firstly, it can be defined as a bilinear map on a \mathbb F-vector space V...

Homework Statement State the definitions of greatest and least elements in terms of strict orderings. Homework Equations Let \leq be an ordering of A and < be a strict ordering on A, and let B \subseteq A. b \in B is the greatest element of B in the ordering \leq if, for every x \in...

What is Energy? - Hard energy definitions Explain this definition: energy is the ability to impart vis viva (mv2) Is it a well definition? Here's a more complex definition: energy is that measure of the physical change of a system that is conserved as a result of temporal displacement...

There is such thing as a orthorhombic body centered crystal lattice. I am wondering why this is the case see the image bellow, we can find a repeating pattern which has a smaller area. A unit cell - must be selected such that it has the highest symmetry and the smallest area, however i do...

There is a discussion of expansion, shear, and vorticity in Wald (p. 217) and in Hawking and Ellis (p. 82). My motivation for comparing them was that although Wald's treatment is more concise, Wald doesn't define the expansion tensor, only the volume expansion. Wald starts off by restricting to...

Analytical definitions vs intuitive (or perhaps "first year") definitions I just began my real analysis course in college and we were given an assignment; a bunch of mathematical terms for us to define. We are asked to define them using two textbooks, one, our first year calculus textbook, the...

I find problems on Bragg diffraction frustrating. I can't tell how the angles are defined, nor the "planes" in the crystal--they look arbitrary. Why can't I just draw a slash through the crystal at any angle I want and get diffraction off the angles I hit with the slash? Is it just that the...

In physics, we use the concept of mass, and we use a unit of mass. It would appear that we must first define the concept of mass, to get to a position where we can establish a unit of mass. Mass not rigorously defined To my knowledge the concept of mass is not rigorously defined in Physics. We...

Hi, I'm trying to save (into a file) definitions of some variables which are of the form Subscript[A,1], Subscript[A,2],... where the subscript is used as an index for the variable. When using the Save command I obtain the error Save::sym: Argument A1 at position 2 is expected to be a...

I have an intuitive understanding of the definitions that will follow, but in my search to find specific definitions I only come up with vague explanations and contentious or subjective uses of those definitions. Please provide some definitions (mathematical) for the following list (and sources...

Homework Statement [PLAIN]http://img528.imageshack.us/img528/7061/37557155.jpg Homework Equations The Attempt at a Solution i don't understand, what can possibly wrong with this :S I checked it so many times over and over but everything seems to be right.. i don't even have this feeling about...

Hello, I thought I understood the Dot Product but Apparently Not! \overline{u} \ \cdot \ \overline{v} \ = (u_x \ \cdot \ v_x) ( \overline{i} \cdot \overline{i} ) \ + \ (u_y \ \cdot \ v_y) ( \overline{j} \cdot \overline{j} ) \ = \ | \overline{u} | | \overline{v} | cos \theta That is the...

Homework Statement Im trying to figure out what the difference is between the following two epsilon delta statements and the kinds of functions they satisfy: For all real numbers x and for all delta>0, there exists epsilon>0 such that |x|<delta implies |f(x)|<epsilon vs. there exists...

Hi All I would like to know if one can present simple definitions for entanglement and concurrence as well as experimental forms to detect them. Sincerely DaTario

In a regular household plug-in, there are 3 prongs: positive, negative, and ground. But, when doing wiring projects, many times they refer to the negative lead as the ground. Why is it that this lead is sometimes referred to as the ground, while other times, the ground is a completely separate...

I thought that temperature is a measure of energy density, which means that at the vacuum energy has a minuscule temperature above absolute zero. However, I read at http://www.Newton.dep.anl.gov/Newton/askasci/1993/physics/PHY59.HTM that "At absolute zero, all motion does not cease,..." which...

Ok I have seen the tensor double dot scalar product defined two ways and it all boils down to how the multiplication is defined. Does anyone know which is correct? I believe the first one is correct but I keep seeing the second one in various books on finite element methods. 1. \nabla \vec{u}...

Help! I need some clarification on definitions, because it seems like I am getting contradictory information. My textbook defines sidereal time as simply the right ascension that is on the local meridian. It further defines sidereal time as being the RA of a star + the hour angle of the...

1. 7.Across: A piece of iron equipment attached to a retort stand to support a gauze or hold a funnel. Down: A metal rod to which you attach clamps and other equipment 2. none 3. This is part of a crossword and am not given any words can you help me find these words because my...

1. 1. a.Metal mesh used to prevent glassware from cracking when heated with a Bunsen burner b. A type of chemical which must be respected and handled carefully in the home and laboratory. 2.None 3. I have to figure out what the word is because its a crossword puzzle and it does...

Definitions of "operation" and "function" Is every operation a function? Is every function an operation? From the definitions I've read, I'm guessing yes. If not, what would be an example of a function that isn't an operation, or an operation that isn't a function?

Rapidity of a particle with speed v can be defined as either c tanh-1(v/c).....(1) or tanh-1(v/c).....(2) The difference is that (2) is a dimensionless hyperbolic angle whereas (1) has the same dimensions as speed (and is nearly equal to speed when small). Equivalent definitions...

I spend some time studying special functions recently. I found two definitions of gamma function, one in form of integral and the other in form of infinite products, and I cannot prove of their equivalence. I found the definition in infinite product form important in proofing many properties of...

Why is the electric field defind as per meter while the magnetic field is defined as per square meter? Does Ampere's law only contain the current density in the solution because of this fact? Couldn't your simplify the Maxwell equations if you changed the SI definitions?

Not really homework, but a typical exercise question, so I figured it's appropriate to post it here. Homework Statement X,Y topological spaces f:X→Y x is a point in X Prove that the following two statements are equivalent: (i) f^{-1}(E) is open for every open E that contains f(x)...

are all "iff"s definitions? are all statements of the form "p if and only if q" definitions or equivalences? can there be any iff statements that are not statements of equivalence?

Was in the shower and I was thinking of this conversation I was having. They were completely ignorant to things as they really are. Instead they took them as how they THINK they are. i.e. science. I assume he does this so that the concepts can fit to whatever he is arguing for or so that he...

I've just encountered the terms Hamiltonian and Lagrangian. I've read that the Hamiltonian is the total energy H = T + U, while the Lagrangian L = T - U, where T is kinetic energy, and U potential energy. In the case of Newtonian gravitational potential energy, U = -G\frac{Mm}{r}. So am I...

just need 2 definitions without proof for an exam tomorrow, don't need to use them for anything just need to be able to quote them but can't find them anyway so if someone could helpfully write them down that would be great 1)simple graph 2)connected graph cheers

Hey guys, I'm new to physics forums I decided to join after seeing how you guys help each other. Well here's my problem I'm sure you guys can answer this. Last semester I had Linear Algebra and I slacked (almost failed) off a bit since it was a 8am lecture and it took place in a movie...

This theorem (if it is proven) comes also from a formula of kinetic energy. Has anyone some suggestions about this one. Definition of f(n): \ f(n)=(2^{n-1}a)Mod(a+b) Definition of g(n): \ \ g(n)= 4f(n)-2(a+b)+1 Definition of h(n): \ h(n)= Sign(f(n))(Sign(g(n))+1)...

Hi. I'm currently doing a course on algebraic topology and thought I was getting on great, was usually getting full marks on homework etc. But I've just got onto a question which should be fairly easy but its suddenly made me realize how badly I understand singular homology. Basically, it says...

[FONT="Arial"][SIZE="5"]Please: I need abook that include this Definitions: 1- Manifold 2- Stable Manifold 3- unstable Manifold thank you.