Between homeomorphism type and Tukey type
Call a compact space $X$ pin homogeneous if every two points $a,b$ are pin equivalent, meaning that there exists a compact space $Y$, a quotient map $f\colon Y\to X$, and a homeomorphism $g\colon Y\to Y$ such that $gf^{-1}\{a\}=f^{-1}\{b\}$. We will prove a representation theorem for pin equivalence...
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Zusammenfassung: | Call a compact space $X$ pin homogeneous if every two points $a,b$ are pin
equivalent, meaning that there exists a compact space $Y$, a quotient map
$f\colon Y\to X$, and a homeomorphism $g\colon Y\to Y$ such that
$gf^{-1}\{a\}=f^{-1}\{b\}$. We will prove a representation theorem for pin
equivalence; transitivity of pin equivalence will be a corollary.
Pin homogeneity is strictly weaker than homogeneity and pin equivalence is
strictly stronger than Tukey equivalence. Just as with topological homogeneity,
no infinite compact $F$-space is pin homogeneous. On the other hand, $X\times
2^{\chi(X)}$ is pin homogeneous for every compact $X$. And there is a compact
pin homogeneous space with points of different $\pi$-character. |
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DOI: | 10.48550/arxiv.1902.06152 |