Natalie Clarius's user avatar
Natalie Clarius's user avatar
Natalie Clarius's user avatar
Natalie Clarius
  • Member for 7 years, 4 months
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53 votes

Why should we care about syntactic proofs if we can show semantically that statements are true?

23 votes
Accepted

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

16 votes
Accepted

Why is $\{\emptyset\} \not = \emptyset$?

11 votes

Curious tautological pattern on"p->p"

11 votes

"Modus moron" rule of inference?

10 votes
Accepted

What is true about a proof system that is complete but not sound?

9 votes
Accepted

What is meant by 'weak' logic?

9 votes
Accepted

Syntactic proof that Peirce's law doesn't hold in simply-typed lambda calculus

8 votes
Accepted

How to compute CNF from truth table

7 votes

Can a conditional be both vacuously true and false?

7 votes

Commutative quantifiers

6 votes

Difference between $\forall xp(x) \vee \forall xq(x)$ and $\forall x(p(x) \vee q(x))$ in english?

6 votes

$ \models A$ vs. $ A \models$

6 votes
Accepted

Contexts in Natural Deduction

6 votes

The interpretation of $\nvdash$

5 votes

What are these symbols in logic called?

5 votes
Accepted

Are $\forall x\forall y(p(x,y)\leftrightarrow p(y,x))$ and $\forall x\forall y p(x,y) \leftrightarrow \forall y\forall x p(x,y)$ tautologies?

5 votes
Accepted

Does the language of the propositional calculus belong to some type of languages in Chomsky hierarchy (regular, CFL, CSL, recursive, r.e.)?

5 votes
Accepted

Is a reasoning valid when no rows where all premises are true in a truth table?

5 votes
Accepted

Does vacuous truth mean non-bivalent truth?

5 votes
Accepted

Natural deduction vs Sequent calculus

5 votes
Accepted

In what sense is logical entailment a set-theoretic relation?

5 votes
Accepted

Are quantifiers a type of logical connective?

5 votes
Accepted

What's the difference between $\vdash$ and $\vDash$?

4 votes

First order logic issue with the truth and scope of quantifiers

4 votes

Does mathematical logic have concepts for "validity" and "soundness" of "arguments"?

4 votes
Accepted

Differences between negations of two similar statements?

4 votes

Ex falso quodlibet with non well-formed formula or false interpretation?

4 votes

“$B$ does not follow from $A$” seems different from $\lnot(A\to B)$

4 votes

Variables vs. Constants, how are they defined in ZFC, and how they differ?

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