PlanetMath (more info)
 Math for the people, by the people.
Encyclopedia | Requests | Forums | Docs | Wiki | Random | RSS  
Login
create new user
name:
pass:
forget your password?
Main Menu
Owner confidence rating: Low Entry average rating: No information on entry rating
Borsuk-Ulam theorem (Theorem)

Call a continuous map $ f:S^m \to S^n$ antipode preserving if $ f(-x)=-f(x)$ for all $ x \in S^{m}$.

Theorem: There exists no continuous map $ f:S^{n} \to S^{n-1}$ which is antipode preserving for $ n>0$.

Some interesting consequences of this theorem have real-world applications. For example, this theorem implies that at any time there exists antipodal points on the surface of the earth which have exactly the same barometric pressure and temperature.

It is also interesting to note a corollary to this theorem which states that no subset of $ \mathbb{R}^{n}$ is homeomorphic to $ S^{n}$.



"Borsuk-Ulam theorem" is owned by RevBobo.
(view preamble)

View style:

See Also: ham sandwich theorem


Attachments:
proof of Borsuk-Ulam theorem (Proof) by bwebste
Log in to rate this entry.
(view current ratings)

Cross-references: homeomorphic, subset, surface, antipodal points, implies, consequences, antipode, continuous map
There are 3 references to this entry.

This is version 3 of Borsuk-Ulam theorem, born on 2001-11-17, modified 2002-02-12.
Object id is 947, canonical name is BorsukUlamTheorem.
Accessed 13114 times total.

Classification:
AMS MSC54C99 (General topology :: Maps and general types of spaces defined by maps :: Miscellaneous)

Pending Errata and Addenda
None.
[ View all 1 ]
Discussion
Style: Expand: Order:
forum policy

No messages.

Interact
post | correct | update request | prove | add result | add corollary | add example | add (any)