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Trismegistos
  • Member for 12 years, 2 months
  • Last seen more than a month ago
  • Łódź, Polska
10 votes
3 answers
3k views

How "Principia Mathematica" builds foundations

9 votes
2 answers
1k views

How it is posible that $\omega$-inconsistency does not lead to inconsistency

8 votes
1 answer
2k views

Model of Robinson Arithmetic but not Peano Arithmetic

7 votes
1 answer
1k views

Book on Curry-Howard Isomorphisms

6 votes
2 answers
2k views

Is constructive proof of non-existence possible

6 votes
3 answers
5k views

Book on modular arithmetic

6 votes
2 answers
164 views

Closed form of generating function consisting of power of two binomials

6 votes
1 answer
335 views

When was contemporary logical notation established

5 votes
5 answers
431 views

Why modal logic needs modalities

5 votes
2 answers
538 views

Sequent calculus and first incompletness theorem

5 votes
1 answer
5k views

Equivalence vs equisatisfiability

4 votes
2 answers
267 views

Are higher order logics substantially stronger than second order

4 votes
3 answers
125 views

When is it correct to treat differential(e.g. $dx$) as regular number

4 votes
3 answers
1k views

Book on lambda calculus logic and type theory

4 votes
2 answers
156 views

How come that two inductive subsets can be different

3 votes
4 answers
3k views

Book on discrete mathematics for self study

3 votes
3 answers
2k views

Book that is more accessible than Shoenfield

3 votes
4 answers
97 views

Limit of function $f(x) = \sqrt{(xa + d)^2 + x^2 b^2} - \sqrt{(xa - d)^2 + x^2 b^2}$

2 votes
1 answer
271 views

Why Induction Axiom is needed if structural induction holds

2 votes
2 answers
501 views

Why Can I divide generating function by $x$

2 votes
3 answers
728 views

Prove $\exists_x(\phi(x) \rightarrow \psi) \iff (\forall_x\phi(x) \rightarrow \psi)$ using natural deduction

2 votes
1 answer
161 views

Show uniqueness of decimal representation using generating funcions.

2 votes
2 answers
192 views

Are $\{X \in 2^{A}:|X|=2\}$, $\{X \subset 2^{A}:|X|=2\}$, $\{X \subset A:|X|=2\}$ first order or second order?

2 votes
2 answers
151 views

Completeness condition in Gödel first incompleteness theorem superflous

2 votes
2 answers
418 views

Are all models of peano arithmetics descibed using first order logic non standard?

1 vote
1 answer
307 views

How it is possible that sound system is inconsistent

1 vote
1 answer
171 views

Why SKI when SK is complete

1 vote
2 answers
234 views

Why relations are defined as the smallest

1 vote
3 answers
15k views

Multiplication of infinite series

1 vote
1 answer
175 views

Second order universal quantifier elimination restriction