# 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.

**3**

**0**answers

### Sunflower lemma in a more general poset?

**-1**

**0**answers

### Can we get rid of the primitive symbol $V$ in Ackermann's set theory this way?

**4**

**0**answers

### Ultrapower of a field is purely transcendental

**8**

**2**answers

### Constructivist defininition of linear subspaces of $\mathbb{Q}^n$?

**3**

**1**answer

### Models of $\mathsf{ZFC}$ with neither $P$- nor $Q$-points

**0**

**1**answer

### Quantifier elimination and where is this quantified convex program in the polynomial hierarchy?

**2**

**2**answers

### (Types of) induction on infinite chains

**11**

**0**answers

### Ordinal-valued sheaves as internal ordinals

**4**

**0**answers

### Is Ackermann's set theory minus class comprehension equal to ZF?

**1**

**0**answers

### Is there a three valued logic whose game semantics corresponds to potentially infinite games?

**2**

**0**answers

### Definable modal logics in first-order structures

**5**

**1**answer

### Amorphous proper classes in MK

**0**

**0**answers

### Combinatorial Logic for Rigid Logic

**7**

**2**answers

### Logic with “co-relations” - sources?

**9**

**0**answers

### Connection between Provability Logic (GL) and geometry?

**8**

**1**answer

### Non-normal numbers definable without parameters in the langauge of differential rings with composition

**9**

**1**answer

### Fibers of the morphism from the free Heyting algebra to the free Boolean algebra

**0**

**0**answers

### Writing Values in Limited Time (Infinite Programs)

**1**

**0**answers

### Arithmetic that corresponds to combinatorial rectangles and cylinder intersections?

**8**

**1**answer

### A question on the ultrafilter number

**4**

**0**answers

### Continuous open self maps on Cantor space

**5**

**1**answer

### Amalgamation via elementary embeddings

**39**

**2**answers

### Ultrafilters as a double dual

**0**

**0**answers

### First order logic query [migrated]

**6**

**1**answer

### Which branches of mathematics can be done just in terms of morphisms and composition?

**4**

**2**answers

### Is the order arithmetic of the positive reals o-minimal?

**4**

**1**answer

### Formalize ignorance

**1**

**1**answer

### An Apparent Incongruity

**2**

**0**answers

### Length of Gaps in Clockable Values

**8**

**1**answer

### Kleene realizability in Peano arithmetic

**42**

**7**answers

### What is an explicit bijection in combinatorics?

**3**

**1**answer

### Restricting First Order Logic to make it decidable [closed]

**7**

**5**answers

### Is there any physical or computational justification for non-constructive axioms such as AC or excluded middle?

**5**

**1**answer

### Is it consistent that $|[\kappa]^{<\kappa}| > \kappa$?

**7**

**1**answer

### Explaining the consistency of PRA and ZF from predicative foundations

**6**

**0**answers

### Can one use forcing as a step to prove the Keisler-Shelah isomorphism theorem?

**7**

**2**answers

### Measure of the numbers with length of $n$ for a nonstandard number $n$

**2**

**1**answer

### Does every uncountably categorical theory have a $\varnothing$-definable strongly minimal imaginary?

**3**

**0**answers

### Partial well-ordering of formulas

**2**

**1**answer

### Termination of “unpacking” abbreviations

**8**

**1**answer

### Is restricting Replacement and Separation enough to make $Q+I\Sigma_n$ bi-interpretable with Set Theory?

**13**

**1**answer

### What are some good lower bounds on the consistency of the failure of the PCF conjecture?

**4**

**0**answers

### Symmetry between V and HOD

**15**

**1**answer

### Why are model theorists so fond of definable groups?

**1**

**1**answer

### Decidability of S2S with real numbers

**14**

**0**answers

### Does inner model theory seek canonical models for large cardinals?

**6**

**2**answers

### Poset dimension and width (Dilworth's theorem)

**4**

**1**answer

### Stronger negation of AC given by rejecting “infinite hat” puzzles

**3**

**1**answer

### Hartogs' Number of the Reals and $\Theta$ without choice

**10**

**4**answers