Let $\Sigma$ be a connected surface with boundary. If $\Sigma$ is compact and orientable, then Lefschetz duality implies that $H^2(\Sigma;\Bbb Z)\cong H_0(\Sigma,\partial \Sigma;\Bbb Z)=0$. Can we compute the second cohomology of $\Sigma$ without compactness or orientability assumptions?
2026-03-26 02:55:43.1774493743
Second cohomology of surface with boundary
314 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail AtRelated Questions in ALGEBRAIC-TOPOLOGY
- How to compute homology group of $S^1 \times S^n$
- the degree of a map from $S^2$ to $S^2$
- Show $f$ and $g$ are both homeomorphism mapping of $T^2$ but $f$ is not homotopy equivalent with $g.$
- Chain homotopy on linear chains: confusion from Hatcher's book
- Compute Thom and Euler class
- Are these cycles boundaries?
- a problem related with path lifting property
- Bott and Tu exercise 6.5 - Reducing the structure group of a vector bundle to $O(n)$
- Cohomology groups of a torus minus a finite number of disjoint open disks
- CW-structure on $S^n$ and orientations
Related Questions in HOMOLOGY-COHOMOLOGY
- Are these cycles boundaries?
- Cohomology groups of a torus minus a finite number of disjoint open disks
- $f$ - odd implies $d(f)$ - odd, question to the proof
- Poincarè duals in complex projective space and homotopy
- understanding proof of excision theorem
- proof of excision theorem: commutativity of a diagram
- exact sequence of reduced homology groups
- Doubts about computation of the homology of $\Bbb RP^2$ in Vick's *Homology Theory*
- the quotien space of $ S^1\times S^1$
- Rational points on conics over fields of dimension 1
Related Questions in SURFACES
- Surface by revolution
- A new type of curvature multivector for surfaces?
- Regular surfaces with boundary and $C^1$ domains
- Hyperplane line bundle really defined by some hyperplane
- 2D closed surface such that there's always a straight line to a point?
- parametrized surface are isometric if all corresponding curves have same length
- Klein bottle and torus in mod $p$ homology
- How can I prove that the restricted parametrization of a surface in $\mathbb{R}^{3}$ ia a diffeomorphism?
- A diffeomorphism between a cylinder and a one-sheeted hyperboloid
- Involution of the 3 and 4-holed torus and its effects on some knots and links
Related Questions in MANIFOLDS-WITH-BOUNDARY
- Regular surfaces with boundary and $C^1$ domains
- "Defining a smooth structure on a topological manifold with boundary"
- Integration of one-form
- Showing that a diffeomorphism preserves the boundary
- Giving a counterexample for the extension lemma of smooth functions
- A question about the proof of Extension Lemma for Smooth functions
- Manifolds with boundary and foliations
- Pullbacks and differential forms, require deep explanation + algebra rules
- Possible to describe random 3D surfaces (geograhical height over limited area) by formula?
- Can you hear the pins fall from bowling game scores?
Related Questions in NON-ORIENTABLE-SURFACES
- When you divide the real projective plane into two subsets, does it always have exactly one non-orientable component?
- Does Day and Night on a Klein bottle have a steady state?
- Example of a non-orientable 3-manifold
- Is there a way to prove algebraically that a Möbius strip is non-orientable?
- What is the 'center circle' of a Mobius Band?
- Criterion for being in a non-orientable 3 manifold?
- Existence af a Frame on the Klein Bottle
- Immersion of non-orientable manifold in a small orientable one
- Paradromic rings and Mobius strip
- How to arrive at an equation of a Roman surface from three points (a triangle)
Trending Questions
- Induction on the number of equations
- How to convince a math teacher of this simple and obvious fact?
- Find $E[XY|Y+Z=1 ]$
- Refuting the Anti-Cantor Cranks
- What are imaginary numbers?
- Determine the adjoint of $\tilde Q(x)$ for $\tilde Q(x)u:=(Qu)(x)$ where $Q:U→L^2(Ω,ℝ^d$ is a Hilbert-Schmidt operator and $U$ is a Hilbert space
- Why does this innovative method of subtraction from a third grader always work?
- How do we know that the number $1$ is not equal to the number $-1$?
- What are the Implications of having VΩ as a model for a theory?
- Defining a Galois Field based on primitive element versus polynomial?
- Can't find the relationship between two columns of numbers. Please Help
- Is computer science a branch of mathematics?
- Is there a bijection of $\mathbb{R}^n$ with itself such that the forward map is connected but the inverse is not?
- Identification of a quadrilateral as a trapezoid, rectangle, or square
- Generator of inertia group in function field extension
Popular # Hahtags
second-order-logic
numerical-methods
puzzle
logic
probability
number-theory
winding-number
real-analysis
integration
calculus
complex-analysis
sequences-and-series
proof-writing
set-theory
functions
homotopy-theory
elementary-number-theory
ordinary-differential-equations
circles
derivatives
game-theory
definite-integrals
elementary-set-theory
limits
multivariable-calculus
geometry
algebraic-number-theory
proof-verification
partial-derivative
algebra-precalculus
Popular Questions
- What is the integral of 1/x?
- How many squares actually ARE in this picture? Is this a trick question with no right answer?
- Is a matrix multiplied with its transpose something special?
- What is the difference between independent and mutually exclusive events?
- Visually stunning math concepts which are easy to explain
- taylor series of $\ln(1+x)$?
- How to tell if a set of vectors spans a space?
- Calculus question taking derivative to find horizontal tangent line
- How to determine if a function is one-to-one?
- Determine if vectors are linearly independent
- What does it mean to have a determinant equal to zero?
- Is this Batman equation for real?
- How to find perpendicular vector to another vector?
- How to find mean and median from histogram
- How many sides does a circle have?