# Questions tagged [lo.logic]

first-order and higher-order logic, model theory, set theory, proof theory, computability theory, formal languages, definability, interplay of syntax and semantics, constructive logic, intuitionism, philosophical logic, modal logic, completeness, Gödel incompleteness, decidability, undecidability, theories of truth, truth revision, consistency.

**8**

**1**answer

### What is the “Prikry–Silver collapse” when CH fails?

**11**

**0**answers

### What are internal complete atomic boolean algebras, intuitively?

**8**

**1**answer

### What is meant by a computational interpretation of univalence?

**6**

**1**answer

### Models with fixed cardinality of non-Lebesgue measurable sets

**1**

**0**answers

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

**5**

**1**answer

### How similar are the c.e. degrees and the CEA(Cohen) degrees?

**8**

**0**answers

### Definable constructions in o-minimal geometry

**5**

**1**answer

### 2-REA PA degrees

**2**

**0**answers

### A question on entailments in sequents

**0**

**1**answer

### Detecting non-negativity of a single constraint by polyhedral constraints - $I$

**5**

**2**answers

### Extending contents

**4**

**1**answer

### Coloring almost-disjointness

**0**

**0**answers

### What is the exact consistency strength of this type-set theory?

**6**

**0**answers

### Are initial segments of coherent measure sequences coherent?

**5**

**2**answers

### Assuming decidable equality but not LEM in HoTT

**1**

**0**answers

### About the sum $\sum_{n=1}^\infty \frac{1}{\mathrm{BB}(n)}$

**4**

**1**answer

### How to compare three supremums of ordinals eventually writable by Ordinal Turing Machines?

**29**

**3**answers

### Alternatives to the law of the excluded middle

**8**

**0**answers

### Bounded Diophantine sets

**2**

**0**answers

### Can we have $\sf V=HTD$? How it relates to $\sf V=HOD$?

**7**

**1**answer

### Categorical semantics of universe levels in dependent type theory

**3**

**2**answers

### Can Z + Ranks + Successor cardinals + Ordinal inaccessibility be equal to ZF?

**7**

**0**answers

### How much is known about the consistency strength of toposes and topos-like categories?

**6**

**3**answers

### Relationship between provable in $RCA_0$ and effectively true

**3**

**0**answers

### Intuitive (topological) explanation of a proof from the HoTT book [closed]

**4**

**1**answer

### Computable change in minimum word length of subgroup elements

**9**

**0**answers

### Decidable membership for subgroup generated by three elements in $F_2\times F_2$

**1**

**1**answer

### Russell's definite description and vacuous truth: a puzzle? [closed]

**1**

**1**answer

### What does the Concordant constructible universe model?

**7**

**0**answers

### Reduced power of an ordered field

**5**

**1**answer

### Equality to a power of a given word undecidable in finitely presented group with decidable word problem

**6**

**1**answer

### Empty preimage under homomorphism of finitely presented groups with decidable word problems

**13**

**1**answer

### Is the diagonal of finitely presented groups computable?

**16**

**2**answers

### Element being trivial in a finitely presented group independent of ZFC

**6**

**1**answer

### Empty preimage under homomorphism of finitely presented groups independent of ZFC

**0**

**0**answers

### Can all unions of sets above some level be constructible before the sets in some relative constructible universe?

**3**

**0**answers

### Empty preimage under homomorphism of finitely presented groups with decidable word problems

**9**

**1**answer

### Do saturated models require choice?

**6**

**0**answers

### How similar can a model of $I\Delta_0$ be to the intersection of all of its definable cuts?

**0**

**1**answer

### Can we choose a sequence of Hilbert spaces?

**11**

**1**answer

### Does every countable set of Turing degrees have an upper bound, without AC?

**4**

**1**answer

### Is decidability reducible to unique decidability (perhaps in multilinear polynomial situations)?

**27**

**1**answer

### Applications of Zorn’s lemma that aren’t chain-complete/directed-complete?

**8**

**5**answers

### Can you do math without knowing how to count?

**1**

**1**answer

### Is existence of this set consistent with Zermelo set theory minus choice?

**0**

**0**answers

### Where does intuitionistic predicate logic live in the arithmetical hierarchy?

**4**

**1**answer

### Universal property of the codomain fibration

**1**

**0**answers

### What is the proof theoretic strength of PCF?

**3**

**0**answers

### Is anything known about $\Delta_n$ bounding?

**0**

**3**answers