# 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.

**13**

**1**answer

### Does “every” first-order theory have a finitely axiomatizable conservative extension?

**5**

**0**answers

### Sunflower / $\Delta$-system 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