Fraenkel \(\cal N19(\precsim)\): Tsukada's Model | Back to this models page
Description: Let \((P,\precsim)\) be a partiallyordered set that is not well ordered; Let \(Q\) be a countably infinite set,disjoint from \(P\); and let \(I=P\cup Q\)
When the book was first being written, only the following form classes were known to be true in this model:
Form Howard-Rubin Number | Statement |
---|---|
14 | BPI: Every Boolean algebra has a prime ideal. |
16 | \(C(\aleph_{0},\le 2^{\aleph_{0}})\): Every denumerable collection of non-empty sets each with power \(\le 2^{\aleph_{0}}\) has a choice function. |
23 | \((\forall \alpha)(UT(\aleph_{\alpha},\aleph_{\alpha}, \aleph_{\alpha}))\): For every ordinal \(\alpha\), if \(A\) and every member of \(A\) has cardinality \(\aleph_{\alpha}\), then \(|\bigcup A| = \aleph _{\alpha }\). |
24 | \(C(\aleph_0,2^{(2^{\aleph_0})})\): Every denumerable collection of non-empty sets each with power \(2^{(2^{\aleph_{0}})}\) has a choice function. |
37 | Lebesgue measure is countably additive. |
60 |
\(C(\infty,WO)\): Every set of non-empty, well orderable sets has a choice function. |
91 | \(PW\): The power set of a well ordered set can be well ordered. |
130 | \({\cal P}(\Bbb R)\) is well orderable. |
165 | \(C(WO,WO)\): Every well ordered family of non-empty, well orderable sets has a choice function. |
191 | \(SVC\): There is a set \(S\) such that for every set \(a\), there is an ordinal \(\alpha\) and a function from \(S\times\alpha\) onto \(a\). |
273 | There is a subset of \({\Bbb R}\) which is not Borel. |
305 | There are \(2^{\aleph_0}\) Vitali equivalence classes. (Vitali equivalence classes are equivalence classes of the real numbers under the relation \(x\equiv y\leftrightarrow(\exists q\in{\Bbb Q})(x-y=q)\).). \ac{Kanovei} \cite{1991}. |
317 | Weak Sikorski Theorem: If \(B\) is a complete, well orderable Boolean algebra and \(f\) is a homomorphism of the Boolean algebra \(A'\) into \(B\) where \(A'\) is a subalgebra of the Boolean algebra \(A\), then \(f\) can be extended to a homomorphism of \(A\) into \(B\). |
361 | In \(\Bbb R\), the union of a denumerable number of analytic sets is analytic. G. Moore [1982], pp 181 and 325. |
363 | There are exactly \(2^{\aleph_0}\) Borel sets in \(\Bbb R\). G. Moore [1982], p 325. |
368 | The set of all denumerable subsets of \(\Bbb R\) has power \(2^{\aleph_0}\). |
369 | If \(\Bbb R\) is partitioned into two sets, at least one of them has cardinality \(2^{\aleph_0}\). |
When the book was first being written, only the following form classes were known to be false in this model:
Form Howard-Rubin Number | Statement |
---|---|
15 | \(KW(\infty,\infty)\) (KW), The Kinna-Wagner Selection Principle: For every set \(M\) there is a function \(f\) such that for all \(A\in M\), if \(|A|>1\) then \(\emptyset\neq f(A)\subsetneq A\). (See Form 81(\(n\)). |
40 | \(C(WO,\infty)\): Every well orderable set of non-empty sets has a choice function. Moore, G. [1982], p 325. |
51 | Cofinality Principle: Every linear ordering has a cofinal sub well ordering. Sierpi\'nski [1918], p 117. |
59-le |
If \((A,\le)\) is a partial ordering that is not a well ordering, then there is no set \(B\) such that \((B,\le)\) (the usual injective cardinal ordering on \(B\)) is isomorphic to \((A,\le)\). |
118 | Every linearly orderable topological space is normal. Birkhoff [1967], p 241. |
144 | Every set is almost well orderable. |
152 | \(D_{\aleph_{0}}\): Every non-well-orderable set is the union of a pairwise disjoint, well orderable family of denumerable sets. (See note 27 for \(D_{\kappa}\), \(\kappa\) a well ordered cardinal.) |
192 | \(EP\) sets: For every set \(A\) there is a projective set \(X\) and a function from \(X\) onto \(A\). |
253 | \L o\'s' Theorem: If \(M=\langle A,R_j\rangle_{j\in J}\) is a relational system, \(X\) any set and \({\cal F}\) an ultrafilter in \({\cal P}(X)\), then \(M\) and \(M^{X}/{\cal F}\) are elementarily equivalent. |
328 | \(MC(WO,\infty)\): For every well ordered set \(X\) such that for all \(x\in X\), \(|x|\ge 1\), there is a function \(f\) such that and for every \(x\in X\), \(f(x)\) is a finite, non-empty subset of \(x\). (See Form 67.) |
Historical background: Let \(A=\{a_{iq} : i\in I, q\) arational number\}; let \(\cal G\) be the set of all permutations \(\pi\) of\(A\) such that \(\pi(a_{iq})= a_{i\pi_i(q)}\) where for each \(i\in I\),\(\pi_i\) is an order automorphism of the rationals. \(S\) is the set of allfinite subsets of \(A\). In this model, the Boolean Prime Ideal Theorem (14)is true and every set of well orderable sets has a choice function (60) istrue. (Since 60 implies \(UT(WO,WO,WO)\) (231) and in every FM model 231implies \((\forall\alpha)UT(\aleph_{\alpha},\aleph_{\alpha},\aleph_{\alpha})\) (23),Form 23 is true.) Form 23 impliesForm 151 and(by Note 120 part 47) 151 + 152 \(\leftrightarrow\) 1. Therefore 152 isfalse. However, the set \((P,\precsim)\) can be embedded into the naturalordering of the cardinals so 59(\(\precsim\)) is false. AC for a wellordered family of sets (40) is false. (In every FM model, 40 + 60 \(\to\)AC, Howard/Rubin [1995b].) Using the fact that the Kinna-WagnerSelection Principle (15) is false and that the Ordering Principle (30) istrue, Krom proves that there is an ordered topological space that is notnormal (118 is false). Form 14 implies 49 (Every partial ordering can beextended to a linear ordering.) and 49 + 51 (Every linear ordering has acofinal sub-well ordering) iff AC. (See Morris [1969] and note121.) Thus,Form 51 is false. Howard [1973] has shown that inevery FM model 14 implies the Weak Sikorski Theorem (317), so 317 is true.Form 40 is false andForm 122 (\(C(WO,<\infty)\)) is true because 60 implies122. Therefore,Form 328 (\(MC(WO,\infty)\)) is false because \(122 + 328\to40\). SinceForm 165 (\(C(WO,WO)\)) is true, (60 implies 165) it follows fromNote 2(8 and 9) that 16 and 24 are also true.
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