Questions tagged [co-tangent-space]

Use this tag for questions about the dual space at a point of the tangent space.

Filter by
Sorted by
Tagged with
0 votes
0 answers
11 views

Notation on tensors and Hamiltonians

I have been reading some notes and at point the author uses a notation I am not aware of and I wanted to figure out what it was. Let $T^*M$ be the cotangent bundle of a compact manifold $M$, and ...
user avatar
  • 4,195
0 votes
0 answers
24 views

Differential form in a variety, from definition and properties

Following Shafarevich Reid - Basic algebraic geometry 1, the differential at $p$ of a polynomial $F(T_1,\dots,T_n)$ is the linear part of the Taylor expansion at $x$ (p. 87), so $$ (dF=)d_xF=\sum \...
user avatar
  • 148
2 votes
0 answers
50 views

Tangent complex to a cotangent stack

Given a smooth Artin cotangent stack $X = T^{*}Y$ can one describe the two-term tangent complex $T_X$ in terms of $T_Y$? The example I am interested in here is the stack of Higgs bundles over a curve $...
user avatar
  • 111
0 votes
1 answer
51 views

basis vector of tangent space of manifold

In this article https://en.wikipedia.org/wiki/Tangent_space, under the section title Basis of the tangent space at a point, it says "... Then for every tangent vector v\in TpM, one has...." ...
user avatar
  • 11
0 votes
0 answers
41 views

Calculation of the Lie derivative of the fundamental one-form in three different ways

I am a physicist who is trying to understand more formal differential geometry in the context of classical mechanics. I came across three ways of computing the Lie derivative of differential one-forms....
user avatar
  • 365
2 votes
0 answers
63 views

Why is the phase space expressed in terms of the cotangent space of the configurational space?

The following is taken nearly verbatim from section 1.1.2.1 Free Energy Computations: A Mathematical Perspective by Mathias Rousset, Gabriel Stoltz and Tony Lelievre. An excerpt, in which the part I ...
user avatar
  • 4,281
0 votes
0 answers
21 views

Compute the dimension of the quotient space $\mathfrak m_a/\mathfrak m_a^2$

Let $\Omega$ be an open set of $\mathbb R^n$ and $\mathcal F(\Omega)$ be the unital commutative ring of infinitely differentiable real functions over $\Omega$. Given $a\in\Omega$, consider $\mathfrak ...
user avatar
  • 531
1 vote
1 answer
38 views

Explicit evaluation of symplectic form on cotangent bundle

Let $M$ be a manifold and denote by $T^*M$ its cotangent bundle. Let $(x,U)$ be a coordinate chart so that $x: U\to \mathbb{R}^{n}$. Let $p\in U$ and $v\in T^*_pM$, then we can write $v = v_i dx^i$ ...
user avatar
  • 121
3 votes
0 answers
70 views

First Chern class of the cotangent bundle vanishes

I'm interested in the first Chern class of the cotangent bundle. I concretely work on the sphere $S^2$, but the reasoning below seems to work for any manifold. I take the symplectic point of view ...
user avatar
  • 121
0 votes
1 answer
58 views

Problem with goniometric function and triangles.

I can't resolve this problem, above there is what I've done. Can you help me? Is there a better way to solve this problem? A triangle $\triangle{ABC}$ is given, where the angle $\angle{BAC}=2{\alpha}$ ...
user avatar
2 votes
0 answers
53 views

References on the ''bi-symplectic'' structure of $T^\ast T \mathcal M$.

Let $\mathcal M$ be a smooth manifold. One can consider two tautological one forms on $T^\ast (T \mathcal M)$: ("Diagonal case") The usual tautological one form on $T^\ast \mathcal E$, ...
user avatar
4 votes
2 answers
190 views

How do we construct the cotangent space?

I am following a graduate course in algebraic geometry and our professor introduced last week the cotangent space at a point p of a variety as the quotient $m/m^2$ where $m$ is the maximal ideal of ...
user avatar
2 votes
0 answers
97 views

Different notation and a little more insight for $dx^i$ based on an alternative definition of the cotangent space

In this post the cotangent space $T_p^* M$ was defined as the quotient $C^\infty(M)/W_p(M)$ where $W_p(M) \subset C^\infty(M)$ is the subspace of smooth functions with vanishing 1st derivative (i.e. ...
user avatar
  • 3,886
1 vote
0 answers
77 views

Metric, tangent and contangent spaces

I have a lot of confusion understanding manifolds, charts, tangent and cotangent vector spaces… Please let me know where I am wrong. Let’s take a flat minkosky space in 4 dimensions and call it $M$, ...
user avatar
5 votes
0 answers
152 views

Possible definition of the cotangent space

This definition is inspired by the book mentioned in this question. As it turns out later it is identical to that in question mentioned in the comment by Paul Frost. The tangent space at $p \in M$ can ...
user avatar
  • 3,886
4 votes
1 answer
142 views

Contangent space as a jet space, (inconsistency ?), Renteln

In Renteln's, Manifolds, Tensors and Forms, p. 81, The cotangent space as a jet space$^*$, we have the following definitions Let $f:M \to \mathbb R$ be a smooth function, $p \in M$, and $\{x^i\}$ ...
user avatar
  • 3,886
2 votes
1 answer
132 views

Confusion about role of covectors in behavior of momentum

This question has been beaten to death on math stackexchange, so I'm a little embarassed I have to ask again, but I am really confused about how/why momentum is a covector. I read Arnold but that didn'...
user avatar
  • 315
0 votes
0 answers
35 views

Induced map between cotangent space is isom when pull back of differential is nonzero

Let $X$ and $Y$ be Riemann surfaces. Let $f\colon X\to Y$ be holomorphic map between them. Let $\omega_1$ be holomorphic differential on $X$, $\omega_2$ be holomorphic differential on $Y$. Suppose ...
user avatar
  • 2,761
2 votes
1 answer
142 views

symplectic geometry: help showing the cotangent lift of an action to a symplectic manifold is a symplectic action

I am following da Silva's lectures on symplectic geometry. She defines the lift of a diffeomorphism as follows: Let $X_1$ and $X_2$ be $n$-dimensional manifolds with cotangent bundles $M_1=T^*X_1$ and ...
user avatar
  • 325
1 vote
2 answers
147 views

Why such cotangent space have $dx_i$ instead of $d/dx_i$ as part of their basis?

DEFINTION OF TANGENT BUNDLE: Given a smooth manifold $M \subset \mathbb{R}^{n}$ embedded as a hypersurface represented by the vanishing locus of a function $f \in C^{\infty}\left(\mathbb{R}^{n}\right)...
user avatar
0 votes
0 answers
41 views

isomorphism of (co)tangent space

Let $X$ and $Y$ be Riemann surfaces. $f:X→Y$ be analytic map. Suppose $f$ induces isomorphism $f*$ between (co)tangent spaces, then, $∀p∈X$, $f'(p)≠0$. How can I prove(understand) this? P.S. Such $f$ ...
user avatar
  • 2,761
1 vote
1 answer
59 views

Specific example Pull-back equality in manifolds

I have to prove the next equality $$ \psi^*\left(\frac{xdx+ydy+zdz}{x^2+y^2+z^2}\right)=dt $$ wher $\psi^*$ is the pull-back of $$ \psi:S^2\times\mathbb{R}\rightarrow \mathbb{R}^3-\{(0,0,0)\}, \ $$ $$ ...
user avatar
0 votes
0 answers
56 views

Cotangent space as a quotient

Let $M$ be a smooth manifold, $p \in M$. Let $I_p$ be the subspace of $C^{\infty}\left ( M \right )$ consisting of smooth functions that vanish at $p$, and let $I_p^2$ be the product of $I_p$ with ...
user avatar
1 vote
0 answers
73 views

Relation between different definitions of the cotangent space of a smooth manifold

There are two ways known to me to define the cotangent bundle on a smooth manifold $X$: Either as the dual bundle of the tangent bundle (see any textbook on differential geometry) or (by abuse of ...
user avatar
  • 367
2 votes
1 answer
181 views

1-forms vs k-forms vs Vector Fields

I'm trying to get a comprehensive understanding of similarities and differences of differential forms and vector fields. As I understand, 1-forms are analogous to vector fields in that for a vector ...
user avatar
  • 195
0 votes
1 answer
139 views

Confused regarding the (dual) basis vectors of the cotangent space $T^*_pM$ of a smooth manifold $M$ and components.

Let $M$ be a smooth $n$-manifold with $p\in M$. Consider the cotangent space $$\operatorname{Alt}^{1}T_pM = \operatorname{Hom}(T_pM,\mathbb{R}) = T^*_pM$$ Now, choosing a chart $(U,\varphi)$ around $p$...
user avatar
  • 2,138
1 vote
1 answer
116 views

Pullback of a Volume Form

Suppose we have a a diffeomorphism between two manifolds, $f: M \rightarrow N$ and a volume form $\Omega$ on $N$. Then is it true that $f^{*}(\Omega) = \Upsilon$ will always be a volume form on $M$? ...
user avatar
  • 195
5 votes
2 answers
345 views

Second derivatives, Hamilton and tangent bundle of tangent bundle TTM

I'm learning the Hamilton formalism of classical mechanics, where a second order differential equation is formalized as two first order differential equations on the cotangent bundle of the ...
user avatar
2 votes
1 answer
236 views

Tautological 1-form on the cotangent bundle is intrinsic using transformation properties

I'm following this lecture in symplectic geometry and I'm trying to show the result stated at 31 minutes that the canonical 1-form on the cotangent bundle $M = T^*X$ is well defined regardless of ...
user avatar
0 votes
1 answer
43 views

Definition of Wave map on manifolds

Let $u: V \rightarrow M$, where $(V,g)$ is a Lorentzian manifold and $(M,h)$ is a Riemannian manifold. The wave equation is defined as $g. \nabla^2 u$. As far as I see, $\nabla^2 u \in \Gamma(T^{*}V \...
user avatar
  • 1,603
2 votes
0 answers
55 views

Reason for defining $df(v)=D_vf$

I'm reading "A Visual Introduction to Differential Forms and Calculus on Manifolds", specifically the section on equivalence of directional derivatives to vectors acting as operators on functions ...
user avatar
0 votes
0 answers
65 views

Attempt to give an alternate definition of Cotangent Space in terms of integration

Let $M$ be the manifold, then we know that tangents space has basis $\frac{\partial}{\partial{x_i}}$ and it acts on $g:M \rightarrow \mathbb{R}$ as $\frac{\partial{g}}{\partial{x_i}}$ and cotangent ...
user avatar
1 vote
1 answer
137 views

local to global definition of symplectic form on cotangent bundle

Show that the form $\omega$ defined locally as $$\omega = \sum dx_i \wedge d\xi_i$$ is globally well-defined on $T^*M$ and restricted to the zero section of $T^*M$ vanishes. Here we consider $M$ to be ...
user avatar
  • 1,734
0 votes
1 answer
130 views

$\mathscr{C}^{k-1}$-manifold structure on the cotangent bundle

Let $X$ be a $\mathscr{C}^k$-manifold of dimension $n$ and atlas $(U_\alpha,\varphi_\alpha)$ (i.e. its atlas is such that the transitions maps $\varphi_\beta\circ\varphi_\alpha^{-1}$ are $\mathscr{C}^...
user avatar
0 votes
2 answers
109 views

What are differential forms?

For a manifold $M$, if we want to speak of "tangent vectors," we often say the tangent bundle $TM$ is the space of tangent vectors. This is sort of an abuse of terminology, I guess you could say, ...
user avatar
  • 450
1 vote
1 answer
149 views

Struck in Diffeomorphism invariance of the line integral

I have been trying to study The Cotangent bundle from An introduction to smooth manifolds by John M Lee. I have been struck at a specific point in the Diffeomorphism Invariance of the integral. The ...
user avatar
  • 184
2 votes
1 answer
153 views

Higgs bundle and spectral curve

I have trouble understanding the following part in E. Wittens paper "More On Gauge Theory And Geometric Langlands": The context is the following: $(E, \varphi)$ is a Higgs bundle with structure group ...
user avatar
  • 1,603
0 votes
0 answers
81 views

Canonical bundle definition

In the article 'More on Gauge Theory and Geometric landlands' by Edward Witten, I have read the term of a 'Canonical bundle'. I've looked that up and as far as I understand, the definition is : $M$ ...
user avatar
  • 1,603
0 votes
0 answers
46 views

Question concerning cotangent spaces of Riemann Surfaces

I have some questions about definitions from Otto Forster's Lectures on Riemann Surfaces. The setup: Let $X$ be a Riemann surface, and allow $U \subset X$ to be open. Define $\mathcal{E}(U)$ to be ...
user avatar
3 votes
1 answer
435 views

How do we define the cotangent space as the quotient of ideals?

I am interested in the definition of the cotangent space as the quotient space of ideals. The definition goes like this: Let $\mathcal M$ be a smooth manifold. $C^\infty (\mathcal M)$ is the ring of ...
user avatar
  • 450
2 votes
0 answers
127 views

Hamiltonian vector field on cotangent bundle

I want to proof the following: Let $Y: Q \rightarrow TQ$ be a global vector field with corresponding flow $\psi_t$. Now let $X:T^{*}Q \rightarrow T(T^{*}Q)$ be the vector field generated by the ...
user avatar
  • 1,603
0 votes
1 answer
85 views

Corresponding flow on cotangent bundle

I have an exercise where it states: Let $Y:Q \rightarrow TQ$ be a complete vector field with flow $\varphi_t$. Let $X : T^{*}Q → T(T^{*}Q)$ be the vector field generating the corresponding flow $\...
user avatar
  • 1,603
0 votes
2 answers
48 views

Is the matrix $dF_p$ invertible when $F=(y^1, \dots, y^n)$ and $(dy^1\big|_p,\dots, dy^n\big|_p)$ is a basis for $T_p^*M$?

Suppose $y^i:M\to \mathbb{R}$ is smooth (for $i=1,\dots, n$) and we define $F:M\to \mathbb{R}^n$ as $F(q)=(y^1(q), \dots, y^n(q))$. If we know that $(dy^1\big|_p,\dots, dy^n\big|_p)$ is a basis for $...
user avatar
  • 2,355
3 votes
1 answer
37 views

Smooth function $y$ that satisfies $dy|_p=w$ for covector $w$.

If $M$ is a smooth manifold, $w\in T^*_pM$, then is it possible to find a smooth function $y:M\to \mathbb{R}$ such that $dy|_p=w$. If it is, is there an easy way to give $y$ explicitly? I have just ...
user avatar
  • 2,355
5 votes
2 answers
409 views

Krull's Principal Ideal Theorem for tangent spaces

In "Foundations of Algebraic Geometry" by Ravi Vakil (page $333$, problem $12.1.B$) there is the following problem Suppose $A$ is a ring, and $m$ a maximal ideal. If $f ∈ m$, show that the Zariski ...
user avatar
  • 901
3 votes
0 answers
168 views

Euler exact sequence for $\mathbb{P}^n$ and toric varieties

I would like to understand explicitly the maps in the Euler exact sequence of $\mathbb{P}^n$: $$0\rightarrow \Omega_{\mathbb{P}^n}^1\rightarrow \mathcal{O}_{\mathbb{P}^n}(-1)^{n+1}\rightarrow \...
user avatar
3 votes
1 answer
131 views

Why are $(q,p)$ in cotangent bundle instead of tangent bundle?

In the book of Frankel, The geometry of Physics, at page 55, he states that [...] Thus, $$p_i^{U} = \sum_j p_j^V (\frac{ \partial q_i^{U}}{\partial q_i^{V} } ),$$ and so the $p’s$ ...
user avatar
  • 7,131
1 vote
3 answers
621 views

Group action induced on the cotangent bundle.

I was reading the wiki on moment maps. [...]Let $N$ be a smooth manifold and let $T^*N$ be its cotangent bundle, with projection map $\pi : T^*N \rightarrow N$. Let $\tau$ denote the ...
user avatar
  • 3,848
2 votes
2 answers
48 views

Chart Transformation in $T^*_x M$

I am confused about a statement in my differential geometry script. It states: $(U,\varphi = (x_1,...,x_n))$ and $(U,\psi = (y_1,...,y_n))$ are charts of a smooth manifold, then $$(dy_i)_x=\sum^n_{\...
user avatar
  • 328
2 votes
1 answer
98 views

Tangent space $T_q(df(M))$ as a subspace of $T_q(T^*M)$

I have been asked to describe the tangents space $T_q(df(M))$ as a subspace of $T_q(T^*M)$ where $f\in C^\infty(M)$ and $df$ is a 1-form (or smooth section of $T^*M$). Here, $df:M\rightarrow T^*M$ ...
user avatar
  • 2,777