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13 votes
0 answers
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Is there any correspondence between Gödel and Kreisel that supports Kreisel's observation that Gödel changed his mind about his 1938 set theory note?

At a conference in 1965 there were some interesting comments made by Kreisel and Mostowski asserting that Gödel later changed his mind regarding his1938 note on his set theory results (see Problems in ...
M. Solomon's user avatar
13 votes
0 answers
882 views

Arguments against Freiling's argument against Continuum Hypothesis

Freiling's axiom of symmetry ($\sf AS$) is known as a justification for falsity of Continuum Hypothesis. Freiling in his 1986 paper, Axioms of symmetry: throwing darts at the real number line, ...
Morteza Azad's user avatar
5 votes
0 answers
947 views

Why are real-valued measurable cardinals never explicitly mentioned in Gödel's "What is Cantor's Continuum Problem"?

It is a matter of mathematical folklore that Gödel "entertained the idea of so called stronger axioms of infinity deciding $CH$...." (this quote from Radek Honzik's paper, "Large ...
Thomas Benjamin's user avatar
5 votes
0 answers
323 views

Can the Kunen inconsistency (or the existence of Reinhardt cardinals) be 'properly formulated' in Ackermann set theory?

In their paper "Generalizations of the Kunen Inconsistency" (arXiv:1106.1951v1 [math.LO]10 Jun. 2011), Hamkins, Kirmayer, and Perlmutter write the following: The first [metamathematical issue--my ...
Thomas Benjamin's user avatar
4 votes
0 answers
409 views

Do you know any deep paradoxes or controversial hypothesis in category theory similar to those we have in set theory?

There is a lot of non-obvious and controversial topics and questions in set theory. From its begining in the first half of 20th century it have generated many paradoxes. For example there are ...
user3048747's user avatar
3 votes
0 answers
342 views

A Question Regarding Boolean-valued Models

What were the intuitions motivating the creation (or discovery, if you will) of Boolean-valued models? I have searched for the Scott-Solovay paper on the subject, but to no avail. There also seems to ...
Thomas Benjamin's user avatar
2 votes
0 answers
305 views

Does this axiomatic system satisfy requirements for founding mathematics?

In this article, the author, F.A.Muller, suggests criteria for a founding theory of mathematics (pp:14-16). The author proposes $ARC$ Class Theory to embody these requirements. The motivation is ...
Zuhair Al-Johar's user avatar
2 votes
0 answers
325 views

The universe and multiverse views of set theory from the perspective of $ZFC^2$

(Note: the 'Second-order $ZFC$' ($ZFC^2$) I am talking about is the theory [in the second order language of set theory consisting of a single non-logical symbol $\in$ ] consisting of the axioms ...
Thomas Benjamin's user avatar
2 votes
0 answers
134 views

A question regarding an analogue of the Kleene $T$-predicate for Koepke's ordinal computability

Does Koepke's notion of ordinal computability admit an analogue of the Kleene $T$-predicate? If so, is the existence of such a $T$-predicate independent of $ZFC$? Also, if one assumes the existence ...
Thomas Benjamin's user avatar
1 vote
0 answers
194 views

Does ${\sf ZC + Universes + ZFC}^V$ meet Muller's criteria for a founding theory of Mathematics?

I was re-thinking Muller's criteria in Sets, Classes and Categories: page 14 for a theory that founds Mathematics. To him, it should be able to be a foundation of Category Theory. He lays down six ...
Zuhair Al-Johar's user avatar
1 vote
0 answers
261 views

Is this theory using defined notions of classes, sets, and membership interpretable in ZFC?

The main difference with this formal theory is that it depends in an essential manner on a defined notion of class, set, and set membership $\in$, rather than the usual appraoch of leaving them ...
Zuhair Al-Johar's user avatar
1 vote
0 answers
163 views

Can "description" of models revive formalism?

A model of a theory is a structure (e.g. an interpretation) that satisfies the sentences of that theory. Wikipedia Let $A$ be a set of sentences in some language that has only one extra-logical ...
Zuhair Al-Johar's user avatar
1 vote
0 answers
125 views

Can $GPK^{+}_{\infty}$ + $AC_{WF}$ prove "$ZFC$ proves that the class of ordinals is not weakly compact for definable classes?

Consider the topological set theory $GPK^{+}_{\infty}$ +$AC_{WF}$, where $GPK^{+}_{\infty}$ is defined as follows (this from Olivier Esser's papers, "An Interpretation of the Zermelo-Fraenkel Set ...
Thomas Benjamin's user avatar
1 vote
0 answers
260 views

Is $\mathit{GPK}^{+}_{ \infty}+\mathit{BAFA}$ inconsistent (and why does it matter)?

Consider Olivier Esser’s alternative axiomatic set theory $\mathit{GPK}^{+}_{\infty}$. Esser defines it as follows (this from his paper "Inconsistency of The Axiom of Choice with The Positive Theory $...
Thomas Benjamin's user avatar
1 vote
0 answers
265 views

Can Dedekind's 'proof' of the existence of infinite sets be properly formulated and carried out in positive set theory?

This question is related to Mikhail Katz's recent mathoverflow question, "Has Dedekind's proof of the existence of existence of infinite sets been analyzed by historians?". Dedekind's 'proof' seems (...
Thomas Benjamin's user avatar
1 vote
0 answers
134 views

A Question Regarding Productive Sets in the Koepke-Koerwien System SO (Sets of Ordinals)

In their paper "The Theory of Sets of Ordinals" (arXiv), Koepke and Koerwien propose a theory SO axiomatizing the class of sets of ordinals in a model of ZFC and show that SO and ZFC are bi-...
Thomas Benjamin's user avatar
1 vote
0 answers
260 views

A question regarding Koepke' s Ordinal Computability in HOD

Consider the following theorem of Koepke-Koerwien-Siders: "A set x of ordinals is ordinal computable [either by ordinal Turing machines or ordinal register machines--my comment] if and only if it is ...
Thomas Benjamin's user avatar
0 votes
0 answers
78 views

'Maximising interpretative power entails maximising consistency strength'?

I'm hoping there is a clear mathematical answer to this question (hence asking it here) rather than anything more exegetical (in which case it's presumably not appropriate for this site). In his paper ...
aidangallagher4's user avatar
0 votes
0 answers
182 views

Erotetic inference and extrinsic justification?

Gödel introduced his notion of what has come to be called extrinsic justification in the following terms: Furthermore, however, even disregarding the intrinsic necessity of some new axiom, and even ...
Kristian Berry's user avatar