The standard multivariate gaussian is given by:
http://upload.wikimedia.org/math/1/c/d/1cd250fc27ef7b7a9da469416333d07f.png
taken from:
http://en.wikipedia.org/wiki/Multivariate_normal_distribution
The parameters can be estimated using...
Homework Statement
Let A = 1 3 2 2
1 1 0 -2
0 1 1 2
Viewing A as a linear map from M_(4x1) to M_(3x1) find a basis for the kernal of A and verify directly that these basis vectors are indeed linearly independant.
The Attempt at a...
Hello everyone,
I would like to ask what's the purpose of identity map? Recently I came across something that apparently use this to find the inverse image of a function F(x) in the form of F(x) = ( f(x) , x ) .
Thanks.
Wayne
Let M be a surface in R3 oriented by a unit normal vector field
U=g1U1+g2U2+g3U3
Then, the Gauss Map G: M to E, of M sends each point p of M to the point (g1(p),g2(p),g3(p)) of the unit sphere E.
Show that the shape operator of M is (minus) the tangent map of its Gauss map: If S and G are...
Can anyone help me with this problem??
Let M be a surface in R^3 oriented by a unit normal vector field
U=g1U1+g2U2+g3U3
Then the Gauss map G:M\rightarrow\Sigma of M sends each point p of M to the point (g1(p),g2(p),g3(p)) of the unit sphere \Sigma.
Show that the shape operator of M is...
This gave me a chuckle.
http://www.economist.com/world/europe/displayStory.cfm?story_id=16003661&source=most_commented
Some folks have had http://en.wikipedia.org/wiki/File:Jesusland_map.svg" , too.
Hello all,
I am using 2008 C++ Express edition on a Windows XP machine and I have the following question regarding use of a map.
How would you use a map to do the following:
The user enters a pipe size, say 1/8" NPS, now there are three possible schedules for that pipe size. They are...
Hi, everyone:
I am confused about the result that every map from a contractible space X into
any topological space Y is contractible.
I think the caveat here is that the homotopy between any f:X-->Y and c:X-->Y
with c(X)={pt.} is that the homotopy is free, i.e., the...
For the theorem: " If v1,...,vr are eigenvectors of a linear map T going from vector space V to V, with respect to distinct eigenvalues λ1,...,λr, then they are linearly independent eigenvectors".
Are the λ-eigenspaces all dimension 1. for each λ1,...,λr.?
Is the dimension of V, r? ie...
D is be a bounded domain in the complex plane. Suppose f : D -->D is a holomorphic automorphism (conformal bijection). Now define f_n(z) = f(f(f(f ..(z) (composed n times ).
Trying (and failing) to show:
(i) the sequence {f_n} has a subsequence that converges either to a constant
or to an...
to my local meridian at various times of the year. An object's declination will be fixed - relatively speaking - but its altitude on my local horizon varies from season to season because of Earth's movement, doesn't it?
Also, if I'm at a lat. 47.3 N shouldn't celestial objects w/dec. of -{90 -...
Is it be possible to produce from the Intensity return of reflective IR laser the true color of the object causing the reflection of the laser? My though is that surfaces of the same material, but of different colors would cause slight changes in wave length of the laser light. These changes...
I have the following mapping (generalized geometric mean):
y(i)=exp\left[{\sum_j p(j|i)\log x(j)}\right]\\ ,\ i,j=1..N
where p(j|i) is a normalized conditional probability.
my question is - is this a contraction mapping?
in other words, does the following equation have a unique...
Homework Statement
My book states as follows:
---
If u and v have the coordinate vectors X and Y respectively in a given orthonormal basis, and the symmetric, linear map \Gamma has the matrix A in the same basis, then \Gamma(u) and \Gamma(v) have the coordinates AX and AY, respectively. This...
Homework Statement
Consider the sine map x{sub t+1} = f(x{sub t}) where f(x) = r*sin(x*pi).
For r > 1/pi there are two fixed points, one at the origin that is unstable, and one elsewhere on the curve. The non-origin fixed point starts out, as you turn r just slightly above 1/pi, as stable...
Homework Statement
Consider the map L from the space of 2x2-matrices to R given by:
L([a b]) = a+ d
([c d])
For clarity, that's L(2x2 matrix) = a + d
The Attempt at a Solution
Im confused how any function of a matrix could possibly equal addition of two scalars, and thus have no...
What is a "phase map"?
I am doing some reading on Structured Light 3D Scanners using digital fringe projection, where a projector shines light (e.g. sinusoidal patterns) onto an object, a camera takes some pictures, and some software uses them to extract a 3D model of the object.
The papers...
Homework Statement
Show that the most general two-dimensional quadratic map with a constant Jacobian is the Henon map:
xn+1=yn+1-ax2n
yn+1=bxn,
where a,b are positive constants.
[/b]
Homework Equations
From the general quadratic map,
xn+1=f1+a1xn+b1yn+c1x2n+d1xnyn+e1y2n...
I'm doing the movement part of the wumpus game. I'm sure many of you are familiar with it, but if not; basically the player starts out in room 1 and s allowed to move into any adjacent room, then from that room into any adjacent room and so on .
The map files that are organized as such:
1...
Field of modulo p equiv classes, how injective linear map --> surjectivity
Homework Statement
Let Fp be the field of modulo p equivalence classes on Z. Recall that |Fp| = p.
Let L: Fpn-->Fpn be a linear map. Prove that L is injective if and only if L is surjective.
Homework Equations...
Homework Statement
Determine the matrix A for the linear map T: R3→R3 which is defined by that the vector u first is mapped on v×u, where v=(-9,2,9) and then reflected in the plane x=z (positively oriented ON-system). Also determine the determinant for A.
Homework Equations
The...
Homework Statement
This problem is from Schaum's Outline, chapter 7 #38 i believe.
Let f: (0, inf) -> [-1,1] be given as f(x) = sin(1/x), where R is given the usual euclidean metric topology and (0,inf) and [-1,1] are given the relative subspace topology.
Show that f is not an open map...
If p is prime, prove that for every function f: Fp -> Fp there exists a polynomial Q (depending on f) of degree at most p-1 such that f(x) = Q(x) for each x in Fp.
Homework Statement
The group G acts transitively from the left on the set X. Let G_x be the little group of the element x \epsilon X. Show that the map i:G/G_x, i(gG_x)=gx is well defined and bijective.
Homework Equations
transitive action:for any two x, y in X there exists a g in G such...
Here is the press conference.
https://www.youtube.com/watch?v=<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/mTnwjd8CF1c&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1"></param><param name="allowFullScreen" value="true"></param><param...
Here is a small segment that was dumped after an error in a program has occurred - that does a lot of memory allocation.b7ee6000-b7ee7000 rw-p 00157000 08:02 72280 /lib/libc-2.9.so
b7ee7000-b7eea000 rw-p b7ee7000 00:00 0
b7eea000-b7ef7000...
Hi,
Say F:A->A where A is a metric space and F is onto. I think it should be true that this implies that F is also one to one. Is there a way to formally prove this? Thanks.
Smooth transition map (easy!?)
Homework Statement
Check the transition map
http://img132.imageshack.us/img132/4341/18142532.png
is smooth in the set for which their images intersect
The Attempt at a Solution
I have thought of two ways to show this.
(1) Show that Φ is a composition...
I am trying to prove that the bth projection map Pb:\PiXa --> Xb is both continuous and open. I have already done the problem but I would like to check it.
1) Continuity:
Consider an open set Ub in Xb, then Pb-1(Ub) is an element of the base for the Tychonoff topology on \PiXa. Thus, Pb is...
Hello,
I just cracked open this abstract algebra book, and saw a problem I have no idea how to solve.
Instruction:
Determine whether the given map \phi is an isomorphism of the first binary structure with the second. If it is not an isomorphism, why not? (Note: F is the set of all functions...
I am trying to read through this paper on the standard model. The ideas seem straightforward enough, but as always, I'm tripping over the "physicist's math" it uses. I was wondering if I can get some clarification or general guidance...
Hi there,
I am trying to plot the coordinates of Supernovae onto what I think is known as a hammer plot i.e a 2D plot representing the surface of a sphere. I have no idea how to do this, and have been searching the internet to no avail. Can anyone offer any advice ? I only have a basic...
Homework Statement
Let V and W be vector spaces over F, and let T: V -> W be a surjective (onto) linear map. Suppose that {v1, ..., v_m, u1, ... , u_n} is a basis for V such that ker(T) = span({u1, ... , u_n}). Show that {T(v1), ... , T(v_m)} is a basis for W.
Homework Equations
Basic...
Im not sure if this is the right section to post this question..
Calculate the differential of the map
f:R^3 -> R^2 , (x ,y ,z)->(xy3 + x2z , x3y2z) at (1 ,2 ,3) in the direction (1 ,-1 , 4)
I know how to get the differential of the map (finding the jacobian matrix) but the only part i am...
Homework Statement
For each of the following pairs of vectors, define an explicit isomorphism to establish that the spaces are isomorphic. Prove that your map is an isomorphism.
a)P3 and R4
b)P5 and M(2,3)
Homework Equations
None
The Attempt at a Solution
a)I know that P3 and R4...
Hi. I'm trying to find the degree of the map of f(g,h)=g.h (i.e. multiplication in g) for fixed g. It is a map G-->G (if we fix g).
We can assign a degree to this map for any topological group for which the last non-zero homology group is Z and proceed like we do for the degree of a map...
Homework Statement
Consider the map phi : C -> I which maps each point of the middle third Cantor set C, considered as a subset of real numbers between 0 and 1 written in base 3 and containing only digits 0 and 2, to the set of real numbers I=[0,1] written in base 2, according to the rule...
Hello all,
I am trying to solve this exercise here:
Let \phi denote the Frobenius map x |-> x^p on the finite field F_{p^n}. Determine the Jordan canonical form (over a field containing all the eigenvalues) for \phi considered as an F_p-linear transformation of the n-dimensional F_p-vector...
Homework Statement
Let D* be the parallelogram with vertices at (-1,3), (0,0), (2,-1), and (1,2), and let D be the rectangle D = [0,1] X [0,1]. Find a T such that D is the image set of D8 under T.
Homework Equations
Not much to say other than T(D*) = D
The Attempt at a Solution...
Homework Statement
Let H, K be subgroups of a finite group G. Consider the map, f : H \times K \rightarrow HK : (h,k)\rightarrow hk. Describe f^{-1}(hk) in terms of h, k and the elements of H\cap K.
Homework Equations
HK = \{hk : h \in H, k \in K \}
f^{-1}(hk)=\{ (h',k') : f(h',k')=hk...
Homework Statement
Consider the map F: C0([a,b],Rn) --> R, F(\phi)=\int\phi(t)\phi(t)dt (This is the integral from a to b). Write F as a composition of three maps, each of which is linear or bilinear. Then use the chain rule and generalized product rule to compute DF(\phi).
Homework...
Map of Bagger-Lambert papers--links, interviews
http://sciencewatch.com/dr/erf/maps/08decerfBaggETRFM/#156486489
This is an interesting development in String/M, very recent, most papers just appeared in the past year or two.
The map shows the most highly cited papers and their approx. degree...
This is a general question...
What is the difference between showing that a map is well-defined and that it is injective?
To prove both can't you show that, given a map x, and elements a,b
if x(a)=x(b) we want to show a=b.
Is a projection a quotient map?
I think a quotient map is an onto map p:X-->Y (where X and Y are topological spaces) such that
U is open/closed in Y iff (p)-1(U) is open/closed in X.
And a projection is a map f:X-->X/~ defined by f(x)=[x] where [x] is the equivalent class (for a...
Homework Statement
Let G={(a,b)/ a,b\inZ} be a group with addition defined by (a,b)+(c,d)=(a+c,b+d).
a) Show that the map\phi:G\rightarrowG defined by \phi((a,b))=(-b,a) is an automorphism of G.
b) Determine the order of \phi.
c) determine all (a,b)\inG with \phi((a,b))=(b,a)...