Statement:

Finite \(\Leftrightarrow\) Dedekind finite: \(W_{\aleph_{0}}\) Jech [1973b]: \(E(I,IV)\) Howard/Yorke [1989]): Every Dedekind finite set is finite.

Howard_Rubin_Number: 9

Parameter(s): This form does not depend on parameters

This form's transferability is: Transferable

This form's negation transferability is: Negation Transferable

Article Citations:
Howard-Yorke-1989: Definitions of finite

Book references
The Axiom of Choice, Jech, T., 1973b
Was sind und was sollen die Zollen?, Dedekind, R., 1888

Note connections:
Note 94 Relationships between the different definitions of finite

The following forms are listed as conclusions of this form class in rfb1: 10, 304, 3, 376, 7, 8, 9, 77, 13, 15, 17, 32, 57, 336-n, 64, 82, 83, 84, 98, 111, 116, 128, 154, 185, 198, 217, 296, 323, 325, 341, 350, 357, 380, 382, 404, 131, 342-n,

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Complete List of Equivalent Forms

Howard-Rubin Number Statement References
9 A For all infinite \(x\), if \(x\) is Dedekind finite,then \(\Cal P(x)\) is is Dedekind finite).  Notes 8 and 94.

9 B \(E(II,IV)\) (Howard/Yorke [1989]): \((\forall x)(x\) is \(T\)-finite if and only if \(x\) is Dedekind finite). Howard/Yorke [1989] and Note 94.

9 C The image of a Dedekind finite set is Dedekindfinite. Jech [1973b] p 161 prob 11.2, notes 11 and 94.

9 D  The union of a Dedekind finite family of finite setsis Dedekind finite. Jech [1973b] p 161 prob 11.4, notes12 and 94.

9 E No Dedekind finite set can be mapped onto \(\aleph_0\).(SeeForm 160.) Monro [1975] and Note 94.

9 F  There is no subset \(A\) of the class of Dedekindfinite cardinals such that  \(A\)  under the usual cardinalordering is order isomorphic to \(\langle{\Bbb R},\le \rangle\).Tarski [1965], Jech [1973b] p 161 prob 6, and Note 94.

9 G Every infinite set has a denumerable subset.Cantor [1895] and G\. Moore [1982] p 9.

9 H If \(A\) is Dedekind finite and \(B\) is Dedekind infinite,then \(A\precsim B\).  G\. Moore [1982] p 28 and Note 94.

9 I If \(\emptyset\in K\) and for all \(A\in K\) and for all\(b\not\in A\), \(A\cup \{b\}\in K\), then every Dedekind finiteset is in \(K\).  G\. Moore [1982] p 28 and Note 94.

9 J The union of a Dedekind infinite family of non-emptysets is Dedekind infinite.  G\. Moore [1982] p 130 and Note 94.

9 K If \(A\) is uncountable and \(B\) is countable, then \(|A-B|=|A|\).  G\. Moore [1982] p 201.

9 L If \(A\) is uncountable and \(B\) is countable, then\(|A\cup B| = |A|\).  G\. Moore [1982] p 202.

9 M If \(\aleph_0 < |A|\) and \(\aleph_0 = |B|\), then \(\aleph_0< |A - B|\).  G\. Moore [1982] p 202.

9 N If \(\aleph_0\le^* m\), then \(\aleph_0\le m\).Lindenbaum/Tarski [1926], G\. Moore [1982] p 216,and Note 69.

9 O \(m\le \aleph_0\) or \(\aleph_0\le m\).Lindenbaum/Tarski [1926] and G\. Moore [1982] p 216.

9 P If \(m + \aleph_0 < n + \aleph_0\), then \(m < n\).Lindenbaum/Tarski [1926] and G\. Moore [1982] p 216.

9 Q If \(m + \aleph_0 = n + \aleph_0\), then \(m = n\) or\(m\), \(n \le\aleph_0\). Lindenbaum/Tarski [1926] and G\. Moore [1982] p 216.

9 R \(E(III,IV)\): Every Dedekind finite set has a Dedekindfinite power set.  Howard/Yorke [1989] and Note 94.

9 S \(E(Ia,IV)\):  Every Dedekind finite set is amorphous.Howard/Yorke [1989], notes 57 and 94.

9 T Restricted Choice:  For every infinite set \(X\) thereis an infinite \(Y\subseteq X\) such that the collection of non-emptysubsets of \(Y\) has a choice function.  De la Cruz/Di Prisco [1998a].

9 U There exists an A-U compact Hausdorff topology onevery set.  Herrlich [1996a] and Note 6.

9 V  There exist an A-U compact \(T_1\) topology on everyset. Herrlich [1996a] and Note 6.

9 W  The Alexandroff compactification of a discrete spaceis A-U compact.  Herrlich [1996a] and Note 6.

9 X In every sequentially compact pseudometric space,every infinite set has an accumulation point. Bentley/Herrlich [1998] and Note 10.

9 Y Every infinite tree has a countably infinite chainor a countably infinite antichain. Keremedis [1999a] andNote 21.