Displaying similar documents to “Incomparable families and maximal trees”

♣-like principles under CH

Winfried Just (2001)

Fundamenta Mathematicae

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Some relatives of the Juhász Club Principle are introduced and studied in the presence of CH. In particular, it is shown that a slight strengthening of this principle implies the existence of a Suslin tree in the presence of CH.

Non-additivity of the fixed point property for tree-like continua

C. L. Hagopian, M. M. Marsh (2015)

Fundamenta Mathematicae

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We investigate the fixed point property for tree-like continua that are unions of tree-like continua. We obtain a positive result if finitely many tree-like continua with the fixed point property have dendrites for pairwise intersections. Using Bellamy's seminal example, we define (i) a countable wedge X̂ of tree-like continua, each having the fpp, and X̂ admitting a fixed-point-free homeomorphism, and (ii) two tree-like continua H and K such that H, K, and H∩ K have the fixed point...

Characterizing chainable, tree-like, and circle-like continua

Taras Banakh, Zdzisław Kosztołowicz, Sławomir Turek (2011)

Colloquium Mathematicae

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We prove that a continuum X is tree-like (resp. circle-like, chainable) if and only if for each open cover 𝓤₄ = {U₁,U₂,U₃,U₄} of X there is a 𝓤₄-map f: X → Y onto a tree (resp. onto the circle, onto the interval). A continuum X is an acyclic curve if and only if for each open cover 𝓤₃ = {U₁,U₂,U₃} of X there is a 𝓤₃-map f: X → Y onto a tree (or the interval [0,1]).