Implications

This non-implication, Form 17 \( \not \Rightarrow \) Form 213, whose code is 4, is constructed around a proven non-implication as follows:

  • This non-implication was constructed without the use of this first code 2/1 implication.
  • A proven non-implication whose code is 3. In this case, it's Code 3: 1062, Form 17 \( \not \Rightarrow \) Form 146 whose summary information is:
    Hypothesis Statement
    Form 17 <p> <strong>Ramsey's Theorem I:</strong> If \(A\) is an infinite set and the family of all 2 element subsets of \(A\) is partitioned into 2 sets \(X\) and \(Y\), then there is an infinite subset \(B\subseteq A\) such that all 2 element subsets of \(B\) belong to \(X\) or all 2 element subsets of \(B\) belong to \(Y\). (Also, see <a href="/form-classes/howard-rubin-325">Form 325</a>.), <a href="/books/8">Jech [1973b]</a>, p 164 prob 11.20. </p>

    Conclusion Statement
    Form 146 <p> \(A(F,A1)\): For every \(T_2\) topological space \((X,T)\), if \(X\) is a continuous finite to one image of an A1 space then \((X,T)\) is  an A1 space. (\((X,T)\) is A1 means if \(U \subseteq  T\) covers \(X\) then \(\exists f : X\rightarrow U\) such that \((\forall x\in X) (x\in f(x)).)\) </p>

  • An (optional) implication of code 1 or code 2 is given. In this case, it's Code 2: 6330, whose string of implications is:
    213 \(\Rightarrow\) 85 \(\Rightarrow\) 62 \(\Rightarrow\) 146

The conclusion Form 17 \( \not \Rightarrow \) Form 213 then follows.

Finally, the
List of models where hypothesis is true and the conclusion is false:

Name Statement
\(\cal N1\) The Basic Fraenkel Model The set of atoms, \(A\) is denumerable; \(\cal G\) is the group of all permutations on \(A\); and \(S\) isthe set of all finite subsets of \(A\)

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