Everything about Klein Bottle totally explained
In
mathematics, the
Klein bottle is a certain non-
orientable surface,
for example, a surface (a two-dimensional
topological space) with no distinct "inner" and "outer" sides. Other related non-orientable objects include the
Möbius strip and the
real projective plane. Whereas a Möbius strip is a two dimensional object with one side and one edge, a Klein bottle is a three dimensional object with one side and
no edges. (For comparison, a
sphere is a three dimensional object with no edges and two sides.)
The Klein bottle was first described in
1882 by the
German mathematician
Felix Klein. It was originally named the
Kleinsche Fläche "Klein surface"; however, this was incorrectly interpreted as
Kleinsche Flasche "Klein bottle", which ultimately led to the adoption of this term in the German language as well.
Construction
Start with a square, and then glue together corresponding colored edges, in the following diagram, so that the arrows match. More formally, the Klein bottle is the
quotient space described as the
square [0,1] × [0,1] with sides identified by the relations (0,
y) ~ (1,
y) for 0 ≤
y ≤ 1 and (
x, 0) ~ (1 −
x, 1) for 0 ≤
x ≤ 1:
»
This square is a
fundamental polygon of the Klein bottle.
Note that this is an "abstract" gluing in the sense that trying to realize this in three dimensions results in a self-intersecting Klein bottle. The Klein bottle, proper, doesn't self-intersect. Nonetheless, there's a way to visualize the Klein bottle as being contained in four dimensions.
Glue the red arrows of the square together (left and right sides), resulting in a cylinder. To glue the ends together so that the arrows on the circles match, pass one end through the side of the cylinder. Note that this creates a circle of self-intersection. This is an
immersion of the Klein bottle in three dimensions.
Image:Klein Bottle Folding 1.svg
Image:Klein Bottle Folding 2.svg
Image:Klein Bottle Folding 3.svg
Image:Klein Bottle Folding 4.svg
Image:Klein Bottle Folding 5.svg
Image:Klein Bottle Folding 6.svg
By adding a fourth dimension to the three dimensional space, the self-intersection can be eliminated. Gradually push a piece of the tube containing the intersection out of the original three dimensional space. A useful analogy is to consider a self-intersecting curve on the plane; self-intersections can be eliminated by lifting one strand off the plane.
This immersion is useful for visualizing many properties of the Klein bottle. For example, the Klein bottle has no
boundary, where the surface stops abruptly, and it's
non-orientable, as reflected in the one-sidedness of the immersion.
The common physical model of a Klein bottle is a similar construction. The
British Science Museum has on display a collection of hand-blown glass Klein bottles, exhibiting many variations on this topological theme. The bottles date from
1995 and were made for the museum by
Alan Bennett.
Clifford Stoll, author of
The Cuckoo's Egg, manufactures Klein bottles and sells them via the
Internet at
Acme Klein Bottle
.
Properties
The Klein bottle can be seen as a
fiber bundle as follows: one takes the square from above to be
E, the total space, while the base space
B is given by the unit interval in
x, and the projection π is given by π(
x,
y) =
x. Since the two endpoints of the unit interval in
x are identified, the base space
B is actually the
circle S1, and so the Klein bottle is the twisted
S1-bundle (
circle bundle) over the circle.
Like the
Möbius strip, the Klein bottle is a two-dimensional differentiable
manifold which isn't
orientable. Unlike the Möbius strip, the Klein bottle is a
closed manifold, meaning it's a
compact manifold without boundary. While the Möbius strip can be embedded in three-dimensional
Euclidean space R3, the Klein bottle cannot. It can be embedded in
R4, however.
The Klein bottle can be constructed (in a mathematical sense, because it can't be done without allowing the surface to intersect itself) by joining the edges of two Möbius strips together, as described in the following
anonymous limerick:
» A mathematician named Klein
Thought the Möbius band was divine.
» Said he: "If you glue
The edges of two,
» You'll get a weird bottle like mine."
It can also be constructed by folding a Möbius strip in half lengthwise and attaching the edge to itself.
Six colors suffice to color any map on the surface of a Klein bottle; this is the only exception to
the
Heawood conjecture, a generalization of the
four color theorem, which would require seven.
A Klein bottle is equivalent to a sphere plus two
cross caps.
Dissection
Dissecting a Klein bottle into halves along its
plane of symmetry results in two mirror image
Möbius strips, for example one with a left-handed half-twist and the other with a right-handed half-twist (one of these is pictured on the right). Remember that the intersection pictured isn't really there. In fact, it's also possible to cut the Klein bottle into a single Möbius strip.
for 0 ≤
u < 2π and 0 ≤
v < 2π.
In this parametrization,
u follows the length of the bottle's body while
v goes around its circumference.
Generalizations
The generalization of the Klein bottle to higher
genus is given in the article on the
fundamental polygon.
Klein surface
A
Klein surface is, as for
Riemann surfaces, a surface with an atlas allowing that the
transition functions can be composed with
complex conjugation one can obtains the so called
dianalytic structure.
References in popular culture
- The TV series Futurama has a brand of beer, Klein's Beer, sold in a Klein bottle.
- Russell Hoban's 2001 novel Amaryllis Night and Day makes extensive use of the Klein bottle as a metaphor. The display of bottles at London's Science Museum, and Alan Bennett himself, also feature in the book.
- In the book Visitors From Oz, the characters construct a Klein bottle to travel from Oz to Earth.
- In the Infocom game Trinity, a giant Klein bottle figures prominently, and is used to help solve one of the puzzles.
- The card Elkin Bottle
shows a 3D representation of a Klein bottle. The name "Elkin" is an anagram of the word "Klein".
- In the animated television show The Real Ghostbusters, Ray Stantz mentions Klein bottles at 01:47 in the episode "Janine Melnitz, Ghostbuster," indicating that they're used as a method of building additional capacity to the containment unit, increasing the amount of ghosts they can store.
Further Information
Get more info on 'Klein Bottle'.
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