In his “The Potential Hierarchy of Sets”, Review of Symbolic Logic 6:2 (2013), 205-28 Øystein Linnebo has proposed a modal set-theory. I was wondering what kind of utility can such a theory have for a mathematician and if there have been other similar attempts to develop theories of that kind.

In the second episode “The Junior Professor Solution” of the 8th season of the Big Bang Theory, there exists a brief moment where Sheldon Cooper references one of his boards with what for a brief moment looked like a bunch of statements in some formal system which has modal operators and quantification. But there also […]

I read the Blue Eyes puzzle here, and the solution which I find quite interesting. My questions: What is the quantified piece of information that the Guru provides that each person did not already have? Each person knows, from the beginning, no fewer than 99 blue-eyed people to be on the island. Then how is […]

Intereting Posts

When does a polynomial take all possible residues modulo any integer?
Strict cyclic order
Show $(2^m-1,2^n+1)=1$ if $m$ is odd
If $f: M\to M$ an isometry, is $f$ bijective?
What does proving the Collatz Conjecture entail?
Open properties of quasi-compact schemes
What does “if and only if” mean in definitions?
How common is the use of the term “primitive” to mean “antiderivative”?
Let G be a finite group with more than one element. Show that G has an element of prime order
non-split extension and Schur multiplier
Using the Limit definition to find the derivative of $e^x$
how to compute this limit
Integrate :$\int\frac{1}{\sqrt{\tan(x)}}dx$
Why do $x^{x^{x^{\dots}}}=2$ and $x^{x^{x^{\dots}}}=4$ have the same positive root $\sqrt 2$?
Do absolute convergence of $a_n$ implies convergence of $K_n=\frac{1}{\ln(n^2+1)}\sum_{k=1}^{+\infty}a_k\frac{3k^3-2k}{7-k^3}\sin k$?