Questions tagged [fibre-bundles]
for questions about fiber bundles, including structure groups, principal bundles, and spaces of sections.
5
votes
1answer
196 views
Classifying space of semidirect product of groups
Assume that $G$ and $H$ are two groups and $G\rtimes _\phi H$ is their semidirect product. My question is, how does the classifying space $B(G\rtimes_\phi H)$ of $G\rtimes _\phi H$ relate to $BG$ and $...
3
votes
0answers
70 views
Torus bundle over spheres
I was wondering what is the classification of all torus bundles over spheres? That is, to classify the fibration
$$
T^m \hookrightarrow M \to S^n.
$$
It is well known that if $n=1$, all fibrations ...
2
votes
0answers
99 views
Fiber-bundle : continuity of transition maps and inverse in general
Let $(E,\pi,B)$ be a locally trivial fibration, with fiber a topological space $F$, $\Phi_i$ and $\Phi_j$ two trivializations over $U_i$ and $U_j$. The transition map from $i$ to $j$ is the ...
4
votes
1answer
150 views
Smooth structure on the space of sections of a fiber bundle and gauge group
Let $\xi$ be a fiber bundle $F\hookrightarrow E\to B$ (where every space is smooth, T2 and second countable), let $\Gamma(\xi)$ be the space of smooth sections. We can complete $\Gamma(\xi)$ with ...
4
votes
1answer
138 views
The existence of the extension of a non-trivial line bundle
In Three Dimensional Gravity Revisted, Witten studied the Abelian Chern-Simons theory in three dimensions.
Let $W$ be a three dimensional manifold. Let $\mathcal{L}$ be a non-trivial line-bundle over ...
2
votes
0answers
31 views
Smoothings over a real interval
I am asking if somebody knows if the following kind of objects are studied somewhere or if there is some kind of obvious obstruction for them to appear.
Let $(X,0) \subset \mathbb{C}^n$ be a germ of ...
5
votes
0answers
87 views
Induced new structures on Poincare dual manifolds
"R. C. Kirby and L. R. Taylor, Pin structures on low-dimensional manifolds (1990)" shows
Given a spin structure on $M^3$, the submanifold $\text{PD}(a)$ can be given a natural induced $\text{Pin}^-$...
5
votes
2answers
119 views
Lifting a diffeomorphism into a spinor bundle automorphism
I know several papers that treat this, but it seems that most of these papers do things very differently with quite different conclusions, so I am confused.
Basically, when one tries to do classical ...
1
vote
0answers
66 views
Explicit description of the scheme obtained by relative gluing data over a base scheme
I have recently been trying to get a better understanding of the projective space bundle of a quasi-coherent sheaf of graded algebras over a scheme $X$. The key idea is the following construction ...
3
votes
1answer
97 views
Naturality of minimal model of a fibre bundle
$\require{AMScd}$
For rational fibrations $F \rightarrow E \rightarrow B$, we have a nice description in terms of sullivan minimal models, namely a commutative diagram of cdga's
$$
\begin{CD}
...
0
votes
1answer
84 views
Is $TS^2\setminus Z$ a $S^2$- fibre bundle on the puntured plane?(Swapping the role of fibre points and base space)
Let $X=TS^2\setminus Z$ where $Z$ is the zero section of the tangent bundle of $S^2$.
Is there a $S^2$- fiber bundle structure on $(X,\mathbb{R}^2\setminus\{0\},q)$ for some continuous fibre map $q$?
3
votes
0answers
189 views
When is the Chern class of a principal $G$-bundle same to the Chern class of the associated complex vector bundle?
Let $P\rightarrow M$ be a principal bundle, with structure group $G$. If $G$ has a representation $\rho:G\rightarrow GL(n,\mathbb{C})$, then we can define its associated vector bundle $E=P\times_{\rho}...
4
votes
0answers
74 views
Representation on square integrable sections of a principal bundle
Let $X\rightarrow Y$ be a smooth principal $G$-bundle for some Lie group $G$. Then $L^2(X)$ has a natural $G$-action determined by fibrewise action of $G$ on $X$.
We have an abstract isomorphism of ...
2
votes
0answers
58 views
Extension of a given section and obstruction cocyles
Let $p:E \to X$ be a fibration with the fiber $F$ where $X$ is a CW-complex. Denote by $U$ the set $U:=D^n \times \{0\} \cup S^{n-1} \times I$ (part of a cylinder) and let $\tilde{f}:U \to E$ be a ...
2
votes
0answers
75 views
Lie algebra bundle associated to a Lie group bundle
I was reading something(page 24) and came across notion of Lie algebra bundles associated to a Lie group bundle.
I am not comfortable with these notions and google gave http://www.pphmj.com/Images/...
4
votes
1answer
110 views
Proper locally trivial bundle is injective on Chow groups
If $X\to Y$ is a map of varieties that is Zariski-locally isomorphic to a projection $U\times P\to U$ with $P$ (smooth) proper, I think the pullback $A_{\bullet}(Y)\to A_{\bullet}(X)$ is supposed to ...
3
votes
0answers
208 views
Is a Difference of Fiber Bundles a Fiber Bundle?
I have a seemingly very basic question in differential topology, but I could not find the answer by a short google search.
Let $M,N$ be smooth manifolds, and let $f:M\to N$ be a smooth fiber-bundle,
...
4
votes
1answer
77 views
Homological class of the fiber in the total space of the one circle bundle
It is a well known fact that (isomorphism classes of) princial $\mathbb{S
}^1$-bundles over a base space $B$ are classified by $B$'s second integral cohomology, $H^2(B;\mathbb{Z}$), by the Euler class....
4
votes
0answers
120 views
Instanton configurations of self-dual and anti-self-dual instantons interplay
Yang-Mills gauge theory is given by the action
$$ S_\text{YM}[A] = \int_M\mathrm{Tr}_\mathfrak{g}(F\wedge \star F)$$
whose Euler-Lagrange equations are the classical equations of motion. The classical ...
1
vote
0answers
100 views
Conventions / Normalizations of Yang-Mills Field Theories
Let the spacetime be 4-dimensional.
In the usual Maxwell theory of Abelian gauge fields $A$, where field strength $F=dA$ one considers the Maxwell action written as
$$
S_{Maxwell}\equiv\int
-\frac{...
3
votes
0answers
127 views
Reference request: classification of principal bundles
I found this theorem in the appendix of Friedrich's "Dirac Operators in Riemannian Geometry"
(Second homotopy classification theorem)
1. For every topological group $G$ there exists a universal ...
2
votes
0answers
52 views
Fibre restriction and Leray–Hirsch
Let $\mathbb{C}P^h\to E\to B$ be a bundle which is cohomologically trivial via Leray–Hirsch, i.e. if we denote $H^*(\mathbb{C}P^h)\cong \mathbb{Z}[\mu]/\mu^{h+1}$, we have a class $\chi\in H^2(E)$ and ...
1
vote
1answer
94 views
Extend a bundle “trivially”
Suppose I have a fibre bundle $E\to B$ with compact fibre. Furthermore, $B$ is open in a larger, compact space, e. g. $B\subseteq B'$. I want to get a map $E'\to B'$ (not a bundle any more!) with
$E'|...
3
votes
0answers
115 views
Classification of fibrations for classifying spaces $B^2\mathbb{Z}_2$ and $BSO(2)$ or $BO(2)$
Thanks to a suggestion by @Igor Belegradek, I am interested also in a simpler problem of this earlier question 301523, by knowing what can we say about the classification of fibrations for classifying ...
5
votes
1answer
265 views
Classification of fibrations for classifying spaces $B^2\mathbb{Z}_2$ and $BSO(3)$ or $BO(3)$
I am interested in knowing what can we say about the classification of fibrations for classifying spaces $B^2M \equiv B^2\mathbb{Z}_2$ and $BG \equiv BSO(3)$ or $BO(3)$.
Here we can take either:
$B^...
2
votes
1answer
214 views
Does every fiber bundle admits flat bundle structure?
It is well known that a bundle which admits a compatible foliation* supports a flat connection and the converse is also true (every smooth and finite dimensional). The question is:
Does every bundle ...
3
votes
2answers
174 views
Signature of the manifold of the multiple fibrations over spheres
We can define the signature of a manifold in $4k$ dimensions.
1) If I understand correctly, the signature $\sigma$ of the manifold of the product space of spheres would always be zero:
$$\sigma(S^...
1
vote
0answers
79 views
Transverse $S^1$ actions on mapping tori
Up until now I have thought that the existence of a transverse $\mathbb{S}^1$ action on a symplectic mapping torus implies that the mapping torus is trivial. Unfortunately I also came up with a ...
7
votes
0answers
190 views
Models for Eilenberg-MacLane space K(Z,3)
Denote by $U(H)$ and $PU(H)$ the unitary and projective unitary groups on an infinite-dimensional Hilbert space $H$. Recall that $U(H)$ is contractible by Kuiper's theorem and that $PU(H)$ is a $K(Z,2)...
1
vote
1answer
149 views
The holonomy map associated to a mapping torus
So I have a rather embarrassing problem, which is not really a "problem", so much as a mental block I seem to be unable to overcome. I am trying to understand the "holonomy map" of a mapping torus. To ...
4
votes
0answers
194 views
Why is any $G$-resolution a principal $G$-bundle?
In the article The Cohomology of Classifying Spaces of H-Spaces by M. Rothenberg and N. Steenrod (https://projecteuclid.org/euclid.bams/1183527356) it is stated as a theorem that if $G$ is a ...
6
votes
1answer
229 views
Action of the spin covariant derivative on gamma matrices?
How does the spin covariant derivative $\nabla^S_{\mu}$ act on gamma matrices satisfying: $\{\gamma^{\mu},\gamma^{\nu}\} = g^{\mu\nu}$, i.e.
$$\nabla^S_{\mu}\gamma^{\nu} = ?$$
where $\nabla^S := \...
5
votes
0answers
178 views
Recovering SU(2)-space when the orbit space is a 3 sphere with 3 singular orbits
Background: Consider $SU(2)$ action on the 6-dim flag manifold $M=SU(3)/T^2$ via left multiplication. We view $SU(2)$ as a subgroup of $SU(3)$ corresponding to $2\times 2$-block. The action is just ...
4
votes
1answer
246 views
A map from a symmetric product of a curve to its Jacobian
Let $C$ be a smooth projective curve over an algebraically closed field $k$, of genus $g$.
It is well known that, after fixing a point $p_0$, the map $C^{(n)}\to J$ sending $\{a_1,\dots,a_n\}$ to $[...
5
votes
0answers
119 views
Projective unitary flat structures of $\mathbb{P}^1$-bundles on Riemann surfaces
Narasimhan and Seshadri proved a rather surprising result about vector bundles on a compact connected complex manifold $X$. That is
Two holomorphic vector bundles arising from unitary representations ...
9
votes
0answers
349 views
Hartshorne's Conjectures about Algebraic Bundles?
In 1978 Hartshorne published a list of 26 open problems about algebraic bundles on projective spaces [Hart], proceeding from an Oxford conference organized by Atiyah.
I understand that many of these ...
3
votes
0answers
62 views
Two questions regarding flat fibre bundles and the corresponding group action on the fibre
Let $F$, $B$ be smooth, closed manifolds and $\phi:\pi_1(B) \rightarrow Aut(F)$ a smooth group action of the fundamental group of $B$ on $F$.
Consider the flat fibre bundle $E_\phi := \widetilde{B} \...
11
votes
1answer
378 views
Equivariant sections of fiber bundles
One of the fundamental facts in fiber bundle theory is the following result for existence and extension of sections (see Thm. 9 in this paper of Palais, and compare with Thm. 12.2 in Steenrod's book):...
5
votes
1answer
160 views
Cup product on flat fiber bundles vs cup product on the corresponding Serre spectral sequence
Let $F \rightarrow E \rightarrow B$ be a flat fiber bundle, $E, F, B$ closed manifolds. Consider $H^*(E, \mathbb{Q})$ and the corresponding Serre spectral sequence with isomorphism $$(*) \ \ \ H^n(E;\...
2
votes
1answer
110 views
non-simple local coefficient system on a fibration of classifying spaces
Long story short; I posted in MSE
https://math.stackexchange.com/questions/2500745/local-system-of-coefficients-on-a-fibration-of-classyfing-spaces
It is well known that if $G$ is a lie group ...
7
votes
0answers
157 views
Smooth trivialization of smooth Hilbert bundles
In page 67 of Topology and Analysis by Booss and Bleecker, it is claimed that any Hilbert bundle is topologically trivial. Clearly, any smooth Hilbert bundle over a smooth manifold is topologically ...
6
votes
0answers
216 views
Obstructions for existence of a fiber wise covering space structure( A bundle of covering spaces)
Let $S^n \times \mathbb{T}^n$ be the trivial Torus bundle over $S^n$.
Assume that we have a continuous fiber preserving map $\phi :TS^n \to S^n \times \mathbb{T}^n$ which restriction to each fiber ...
2
votes
1answer
245 views
Compute cohomology of flat fiber bundles - does this always work?
Edit: This has been answered in this thread Are there compact flat fiber bundles with "truly" infinite structure group?.
Setting
Let $p: E \rightarrow B$ be a flat fiber bundle with fiber ...
4
votes
0answers
119 views
Equivalence of Flat Fiber Bundles vs Equivalence of Group Actions on the Fiber
Let's consider all flat fiber bundles with base space $B$ and fiber $F$, where $B$ and $F$ are compact and at least CW-complexes. (perhaps even topological/smooth manifolds if that helps)
All those ...
4
votes
0answers
183 views
Complete proof of Homotopy invariance of a numerable fiber bundle based on CHP
Homotopy invariance of numerable fiber bundle: let $\xi = (E,π,B)$ (i.e. $\pi : E \to B$) a numerable topological fiber bundle, $X$ a topological space, and $f,\,g : X \to B$ two continuous ...
8
votes
1answer
162 views
Extensions of Fried's Theorem: Surface bundles over Circles and Flows on 3 Manifolds
The Thurston Polytope provides a way to organize information about the embedded surfaces living in a 3-manifold.
His amazing theorem, often called the "Fibered Faces" Theorem, says that if you have ...
8
votes
2answers
533 views
Is a topological fiber-bundle, whose total space admits a retraction onto a fiber, trivial?
Let $\xi = \pi \colon E \to B$ a topological fiber bundle with connected base $B$, $E_x = \pi^{-1}(x)$ the fiber at $x \in B$, $j \colon E_x \hookrightarrow E$ the canonical injection, and let suppose ...
7
votes
1answer
318 views
Are topological fiber bundles on the same base with homeomorphic fibers isomorphic?
First I apologize because this is not a research question, but I can't get any answer on MathStackExchange...
Let $\pi \colon E \to B$ and $\pi' \colon E' \to B$ two topological fiber bundles on the ...
3
votes
1answer
115 views
Embeddings of fiber bundles
While reading GMTW - The homotopy type of the cobordism category (https://arxiv.org/abs/math/0605249, p. 16) I found the following passage:
Lef $f:W\to \mathbb{R}$ be the projection. Then $(\pi_2,...
3
votes
0answers
172 views
How can I find the differential in the Serre spectral sequence for this sphere fibration?
Consider the assocaited sphere bundle $$S(E) \to \mathbb{P}^n$$ for the vector bundle $\mathcal{O}(k)\oplus \mathcal{O}(l) \to \mathbb{P}^n$. Is there a way to determine the differentials
$$
d_4^{p,m}:...
