Subspaces Definition and 317 Threads

Hi, everyone: I have been trying to show this using the following: Given f: Y-->X IF S^n ~ Y_f(x) , then S^n deformation-retracts to Y , and ( not sure of this) also is homeomorphic to Y (I know Y_f(x) is homotopic to Y ) . But ( so I am branching out into more...

a) {(x1,x2,x3) | x1+x2 ≥ 0} b) {x∈R3 |proj(1,1,1) (x) ∈ Sp({(1,1,1)})} Prove the set is or is not a subset of R n I have no idea how to solve this. Our textbook gives NO examples of how to prove these Please help me get started, a related example would be great too. :) Thanks-...

Homework Statement I'm unclear about this statement being wrong or not: if C is an x-dimensional subspace of Rn, then a linearly independent set of x vectors in C is a basis for C The Attempt at a Solution I think that it must be a basis since it has independent vectors and it is in x...

Homework Statement Let u be a vector where u = [4 3 1]. Let A be the set of all vectors orthogonal to u. Show that A is subspace of R^3. Then find the basis for A. Homework Equations The Attempt at a Solution For showing that A is a subspace... Zero vector is in A because...

Let H and K be subspaces of a vector space V. Prove that the intersection K and H is a subspace of V. Intuitively I can see that this is true... Both H and K must be closed under vector addition and scalar multiplication so there intersection must also be closed under both those. How do i...

If V and W are 2-dimensional subspaces of R4 , what are the possible dimensions of the subspace V intersection W? I am new to subspaces, so I have no clue to this question. Help guys! Options: (A) 1 only (B) 2 only (C) 0 and 1 only (D) 0, 1, and 2 only (E) 0, 1, 2, 3, and 4

Homework Statement Let S be a nonempty set and F a field. Prove that for any s_0 \in S, {f \in K(S,F): f(s_0) = 0}, is a subspace of K(S,F). K here is supposed to be a scripted F. Homework Equations The Attempt at a Solution I don't know how to approach this problem. I know the three...

Homework Statement Prove or give a counterexample: If U is a subspace of V that is invariant under every operator on V, then U = {0} or U = V.Homework Equations U is invariant under a linear operator T if u in U implies T(u) is in U.The Attempt at a Solution Assume {0} does not equal U does not...

Hi, I have thius problem to solve. Please, help me! 1. Prove or disprove if U, V, W are subspaces of V for which U (dir sum) W = V (dir sum) W then U=V Thank you in advance!

Homework Statement Let V be a vector space over an infinite field. Prove that V is not the union of finitely many proper subspaces of V. The attempt at a solution Suppose V is the union of the proper subspaces U1, ..., Un. Let ui be a vector not in Ui. If u1 + ... + un is in the union...

Let \vec{u},\vec{v},\vec{w} be fixed vectors in Rn. Define S to be the set of all vectors in Rn which are linear combinations of the form k_1 \vec{u}+k_2 \vec{v}+3 \vec{w}, where k_1,k_2 \in R. Is S a subspace of Rn? Im a little stuck with this one. I've tried defining two vectors...

hello again I was asked if the set of all uppertriangular nxn matricies are a subspace of Mnn, how would you check if it has a zero vector and closed under addition and multiplication ? and why did they ask for the upper triangular matrix instead of the lower one? or either

There are more answers to this problem, but I'm not sure how to approach it. The subspaces of R^3 are planes, lines, R^3 itself, or Z containing only (0,0,0,0). b. Describe the five type of subspaces of R^4 i. lines thru (0,0,0,0) ii. zero (0,0,0,0) iii. planes thru (0,0,0,0)...

I have a few questions here, my main problem is not understanding the notations used, hence not understanding the questions. Homework Statement 1. Do the vectors j_{1}= (1,0,-1,2) and j_{2}= (0,1,1,2) form a basis for the space W = {(a,b,c,d) l a - b + c = 0, -2a - 2b + d =0} ? 2...

subspaces and dimension! Consider two subspaces V and W of R^n ,where V is contained in W. Why is dim(V)<= dim(W)...? "<=" less than or equal to

So I'm considering dimensions of real vector spaces. I found myself thinking about the following: So for the vector space R2 there are the following possible subspaces: 1. {0} 2. R2 3. All the lines through the origin. Then I considered R3. For the vector space R3 there are the...

Homework Statement Without computing A, find the bases for the 4 fundamental subspaces. [1 0 0][1 2 3 4] [6 1 0][0 1 2 3]=A=LU [9 8 1][0 0 1 2] Homework Equations N/A The Attempt at a Solution There was an "example" in the book. It just showed the answers. It was: [1 0...

Homework Statement Let V be a vector space over a field F and let X, Y and Z be a subspaces of V such that X\subseteqY. Show that Y\cap(X+Z) = X + (Y\capZ). (Hint. Show that every element of the LHS is contained on the RHS and vice versa.) Homework Equations The Attempt at a...

Homework Statement Which of the following subsets of the vector space R^R of all functions from R to R are subspaces? (proofs or counterexamples required) U:= f \inR^R, f is differentiable and f'(0) = 0 V:= f\inR^R, f is polynomial of the form f=at^2 for some a\inR = There exists a...

Another linear algebra question! What a surprise! :rolleyes: Homework Statement If U1, U2, U3, are subspaces of a finite-dimensional vector space, then show dim(U1 + U2 + U3) = dimU1 + dimU2 + dimU3 - dim(U1 \cap U2) - dim(U1 \cap U3) - dim(U2 \cap U3) + dim(U1 \cap U2 \cap U3) or give a...

Homework Statement Give an example of a nonempty subset U of R2 such that U is closed under scalar multiplication, but U is not a subspace of R2. Homework Equations The Attempt at a Solution I think I have it, but I just want to make sure it's right: Let U = {(x, x + 2)} | x is...

[SOLVED] Projections on subspaces Homework Statement I have some questions on this topic: 1) If I have an orthonormal basis for a subspace U and I have a vector A, and I want to find the orthogonal projection of A onto U, then I use the expression written here...

Homework Statement Let {W_1,W_2,W_3,...} be a collection of proper subspaces of V (i.e. W_i not=V) such that W_i is a subset of W_(i+1) for all i. Prove that U(W_i) (i from 1 to infinity) is a proper subspace of V The Attempt at a Solution I've already proven that U(W_i) is a subspace of...

Homework Statement What is an example of a subset of R^2 which is closed under vector addition and taking additive inverses which is not a subspace of R^2? R, in this question, is the real numbers. Homework Equations I know that, for example, V={(0,0)} is a subset for R^2 that...

I don't understand this, can someone help?: What is an example of a subset of R^2 which is closed under vector addition and taking additive inverses which is not a subspace of R^2? R, in this question, is the real numbers. Thanks!

Hi to all, I really need help fast. How do I solve this question? A solution would be much appreciated. THANKS A MILLION! ======================================================= Let S1 and S2 be the two subspaces in a vector space V. Show that the intersection of S1 and S2 is also...

I am totally lost on the following questions. What does exhibit mean? 1) Show that the given set H is a subspace of ℜ^3 by finding a matrix A such that N(A) = H (in this case, N(A) represents the null space of A). 2) Exhibit a basis for the vector space H. a b {for all R^3...

Homework Statement Prove or give a counterexample: If U is a subspace of V that is invariant under every operator on V, then U = {0} or U = V. Assume that V is finite dimensional. The attempt at a solution I really think that I should be able to produce a counterexample, however...

Homework Statement Find subspaces A, B, and C of \mathbb{R}^3 so that A \cap B \cap C \ne \{\vec{0}\} and (A + B) \cap C \ne A \cap C + B \cap C. You can specify a subspace by the form A = span\{\vec{e}_1, \vec{e}_2\}.Homework Equations A + B is the set of all vectors in \mathbb{R}^3 of the...

I just wanted to know if subspace A + subspace B is the same as the "union of A and B".

Hello Everyone. In a thread in this forum relating to a problem on Subspaces I read that as long as a Vector SubSpace is closed under addition and multiplication we always have the zero vector. I can see that we can always get the zero vector but do we not have to define a zero vector first...

Homework Statement Let U be a unitary operator on an inner product space V, and let W be a finite-dimensional U-invariant subspace of V. Prove that (a) U(W) = W (b) the orthogonal complement of W is U-invariant (for ease of writing let the orthogonal complement of W be represented by...

I came across a problem in linear algebra asking me to find for which values of s the following set: R={(x,y,z,w) belongs to R^4; x+y+sz-w=s^2-2s} is a subspace of R^4 with respect to the usual additoin and scalar multiplication. Any idea to solve this question? Thanks in advance

"Is it possible to derive the Schwarzschild metric from Killing vectors, thus saving all that work with the Ricci tensor etc."

Hello, can anyone tell me if I understand this right? :rolleyes: I have a t-invariant subspace with basis B, and I extend the basis B to be a basis B' for the entire vector space by adding L.I. vectors to it. Then I put B under a linear transformation, T:V --> V, and I will get a set of...

Homework Statement I'm given a subspace in F^5 (not sure how to note that online) and asked to find a basis and dimension for it. I know it should be really easy, but ... Homework Equations We're given subspace W1 = {a1,a2,a3,a4,a5) in F^5: a1-a3-a4=0} . We also know from linear...

Homework Statement Determine whether the set of polynomials of degree 3 form a subspace of P(4) Homework Equations P(4) = c_3 x^3 + c_2 x^2 + c_1 x + c_0 The Attempt at a Solution \alpha P(4_1) = \alpha c_3 x^3 + \alpha c_2 x^2 + \alpha c_1 x + \alpha c_0 This just scales the...

hi, I am confused about vector spaces and subspaces. I've just started a book on linear algebra, and i understood the 1st chapter which delt with gaussian reduction of systems of linear equations, and expressing the solution set as matricies, but the 2nd chapter deals with vectors and I'm...

V = F(R, R), the vector space of all real valued functions f(x) of a real variable x. Which are subspaces of V? (A) {f | f(0) = 0} (B) {f | f(0) = 1} (C) {f | f(0) = f(1)} (D) C^0(R) = {f | f is continous} (E) C^1(R) = {f | f is differentiable and f' is continous}...

Consider 2-by-2 matrices \mathbf{A} =\left( \begin{array}{cc}a & b \\c & d \\\end{array} \right) \in \mathbbm{R}^{2 X 2}. Which of the following are subspaces of \mathbbm{R}^{2 X 2}? (A) {A | c = 0} (B) {A | a + d = 0} (C) {A | ad - bc = 0} (D) {A | b = c} (E) {A | Av = 2v}, where...

Greetings, I'd like to know how one goes about finding a basis for the intersection of two subspaces V and W of a given vector space U. I am aware of the identity V \cap W = (V^{\per} \cup W^{\per})^{\per} (essentially the orthogonal space of the union of orthogonal spaces of V and W), but this...

i've been having some trouble with my linear algebra homework and I am wondering if you guys could give me some insight or tips on these problems: Let v be any vector from V, and let a be any real number such that av=0. Show that either a=0 or v=0. - i was thinking about assuming the...

A and B are two subspaces contained in a finite vector space V and dimA = dimB Can we conclude A=B? In that subspaces A and B are really the same subspace and every element in one is in the other? I think yes because if dimA=dimB then their basis will contain the same number of vectors...

prove that Z(v,T)=Z(u,T) iff g(T)(u)=v, where g(t) is prime compared to a nullify -T of u. (which means f(t) is the minimal polynomial of u, i.e f(T)(u)=0). (i think that when they mean 'is prime compared to' that f(t)=ag(t) for some 'a' scalar). i tried proving this way: suppose, g(T)(u)=v...

How do you find the intersection of subspaces when the subspaces are given by the span of 3 vectors? For example, U is spanned by { X1 , X2 , X3} and V is spanned by { Y1, Y2, Y3}. Thanks in advance.

infinitely many "subspaces" in R3 ? In R3, there are zero, 1, 2, 3 dimensional subspaces. But how can I express them with 'specific' example, using variables x,y,and z?

I'm so lost! 1. W is the set of all vectors in R4 such that x1 + x3 = x2 + x4. Is W a subspace of R4 and Why? How do i get started here? I'm thoroughly confused on this whole idea of vector spaces and such.

Suppose U is a subspace of V. Then U+U = U+{0}=U, right? So the operation of addition of vector spaces does not have unique additive identities. *typo in title

Hello, just wondering if my proof is sufficient. Here is the question from my book: Show that the following sets of elements in R2 form subspaces: (a) The set of all (x,y) such that x = y. ------- So if we call this set W, then we must show the following: (i) 0 \in W (ii) if v,w \in W, then...

Hi, can someone shed some light on the following question. It's been bothering me for a while and I'd like to know where I went wrong. Here is what I can remember of the question. The following is an inner product for polynomials in P_3(degree <= 3): \left\langle {f,g} \right\rangle =...