# Questions tagged [non-orientable-surfaces]

For all questions about Möbius bands, Klein bottles, projective planes or surfaces built from these (via surgeries, gluings...), intersection or boundary problems, embeddings...

12 questions
59 views

### What goes wrong with Stokes theorem if a surface is not orientable?

For the Möbius strip parametrized by $\{\sigma(\theta,r)=((1+r\sin(\theta/2))\cos\theta,(1+r\sin(\theta/2))\sin\theta,r\cos(\theta/2))\ \mid \\ (\theta,r)\in A=(0,2\pi)\times(-1/2,1/2) \}$ we get ...
179 views

### Is there a way to prove algebraically that a Möbius strip is non-orientable?

I am doing my HL Maths coursework on non-orientability of surfaces and am trying to prove whether a möbius strip is orientable or not (of course it isn't) Is there a way to prove algebraically that a ...
71 views

### Paradromic rings and Mobius strip

I'm working on a project about the differences between the original Möbius strip, a strip with an additional even number of half-twists, and a strip with an additional odd number of half-twists. This ...
277 views

### Does this manifold have a name?

EDIT: In an attempt to not let the bounty go to waste, I will consider responses that give reasonable guesses of what the involved surfaces are, WITHOUT requiring parametrizations. While using ...
60 views

### Using fundamental polygons to prove $PR^2\# T^2 = PR^2\# PR^2 \# PR^2$.

Background Let $P^2$ denote the real projective plane, and $T^2$ the torus. These generate a monoid where the operation is the connected sum. This monoid is abelian, so for notational brevity, we ...
66 views

I have three points (for example, A( 1, 1, 0 ) B( 2, 1, 0 ) C( 1.5, 0, 0 ), origin at O( 0, 0, 1000 ) ), with which I am creating what I believe is a Roman surface ($x^2y^2 + y^2z^2 + z^2x^2 - r^2xyz =... 0answers 14 views ### A non-orientable surface$S$such that$T_pS$is time-type. I'm currently taking a course in Semi-Euclidean (Semi-Riemannian) Geometry and am given the task to give an example of a non-orientable surface$S$in$\mathbb{R}^3_1$which is time-type. With the ... 0answers 58 views ### Criterion for being in a non-orientable 3 manifold? I'm trying to wrap my head around the concept of orientability as an intrinsic property of a manifold. Assume I'm in some (3-dim) manifold for which I'd like to decide its orientability; what could I ... 0answers 32 views ### Is there an intuitive way to see why$\mathbb{P}^2$is non-orientable? In the book of D. Chillingworth titled Differential Topology with a view to applications, at page 141, the author argues that [...]$\mathbb{P}^2$can be described equivalently as the set of all ... 0answers 17 views ### Given a free involution$i$on a finite graph$G$, is there a minimal embedding of$G$such that$i\$ is facial?

This question comes from my own Bachelor-thesis work. I am exploring the 1-2-inifity conjecture, or Negamis conjecture, and I am trying to see what happens if one tried to extend Negamis result that a ...