New posts in first-order-logic

Nonexistence of independent axiomatization of a theory in a finite language.

first-order-logic

Deduction Theorem: only works with closed formulas?

logic predicate-logic first-order-logic

Is it possible to convert $\forall$ quantifiers to $\exists$ quantifiers without negation?

logic first-order-logic quantifiers

Online tools for checking validity of classical, intuitionistic, ... logic formulas?

propositional-calculus predicate-logic first-order-logic online-resources constructive-mathematics

Restrictions on the use of universal generalization

logic predicate-logic first-order-logic natural-deduction

What set of formal rules can we use to safely apply Universal/Existential Generalizations and Specifications?

logic first-order-logic quantifiers

Different meanings of "=" in first-order logic and in set theory

set-theory first-order-logic

What is the logical flaw in this reasoning? Abusing $T \equiv T \vee F$.

logic first-order-logic predicate-logic

Definition of "substitutable" in Mathematical Logic

logic first-order-logic

Why do first order languages have at most countably many symbols?

logic model-theory first-order-logic

Are all universal formulas true and all existential formulas false in the empty model?

first-order-logic

Which rule of logic is used on $\delta$ in this proof of the squeeze theorem

calculus limits logic first-order-logic epsilon-delta

Simplest axiom that entails the existence of an infinite set

set-theory first-order-logic predicate-logic infinity axioms

What exactly is a contradiction and how does it differ from falsity?

logic propositional-calculus first-order-logic predicate-logic

How is "interpretation" used differently in propositional vs. first-order logic?

logic definition propositional-calculus first-order-logic model-theory

Which of the following statements express the given sentence? Why not both?

logic first-order-logic

Exercise 2.5.5 david marker's [closed]

logic first-order-logic model-theory

Prove or disprove: if Γ ⊢ α and Γ ⊆ ∆ then ∆ ⊢ α

logic first-order-logic provability

How to prove that Gödel's Incompleteness Theorems apply to ZFC?

logic set-theory predicate-logic first-order-logic incompleteness

Why isn't there a first-order theory of well order?

model-theory first-order-logic