PlanetMath (more info)
 Math for the people, by the people. Sponsor PlanetMath
Encyclopedia | Requests | Forums | Docs | Wiki | Random | RSS  
Login
create new user
name:
pass:
forget your password?
Main Menu
Owner confidence rating: Medium Entry average rating: No information on entry rating
Aronszajn tree (Definition)

A $\kappa$ tree $T$ for which $|T_\alpha|<\kappa$ for all $\alpha<\kappa$ and which has no cofinal branches is called a $\kappa$ Aronszajn tree. If $\kappa=\omega_1$ then it is referred to simply as an Aronszajn tree.

If there are no $\kappa$ Aronszajn trees for some $\kappa$ then we say $\kappa$ has the tree property. $\omega$ has the tree property, but no singular cardinal has the tree property.




"Aronszajn tree" is owned by Henry.
(view preamble | get metadata)

View style:

See Also: tree (set theoretic), antichain, Suslin tree, weakly compact cardinals and the tree property

Also defines:  Aronszajn tree, $\kappa$-Aronszajn tree, tree property

Attachments:
proof that $\omega$ has the tree property (Proof) by Henry
example of Aronszajn tree (Example) by Henry
Log in to rate this entry.
(view current ratings)

Cross-references: singular cardinal, cofinal branches
There are 4 references to this entry.

This is version 7 of Aronszajn tree, born on 2002-07-27, modified 2006-06-24.
Object id is 3217, canonical name is Aronszajn.
Accessed 7460 times total.

Classification:
AMS MSC05C05 (Combinatorics :: Graph theory :: Trees)
 03E05 (Mathematical logic and foundations :: Set theory :: Other combinatorial set theory)

Pending Errata and Addenda
None.
[ View all 4 ]
Discussion
Style: Expand: Order:
forum policy

No messages.

Interact
post | correct | update request | add derivation | add example | add (any)