All Questions
7 questions
5
votes
0
answers
231
views
Schröder and graphical logic?
I was actually surprised by a comment by John Baez over at the n-Category Cafe about his surprise that Ernst Schröder, a mathematician of whom he had known through Schröder's work on mathematical ...
- 10.5k
2
votes
1
answer
232
views
Question on countably homogeneous structures
A homogeneous structure is a countable first order structure $M$ over a relational language such that any isomorphism between finite substructures of $M$ can be extended to an automorphism of $M$.
...
- 663
2
votes
1
answer
255
views
Is the logic of directed graphs generated by a finite set of formulae?
We consider the logic of reflexive directed graphs, i.e. the set
${\bf L}_1$ of those propositional formulae $\varphi$ in the variables $p_i$, which are valid in exactly these graphs.
It is a proper ...
- 567
6
votes
2
answers
477
views
Heyting algebras originating from directed graphs
The category RefGph of reflexive directed graphs is the functor
category $\hat{∆}_1=\mbox{Fun}(∆^◦_1,$Set), where $∆_1$ is
the simplex category truncated at level 1.
Hence the poset Sub(X) of ...
- 567
2
votes
0
answers
163
views
Graph theoretical representation of Wang Tile
We note that for one dimensional tiling problem of Wang Tile could be represented by a graph. Each cycle on the graph represents a periodic solution.
However, is there a well established counter-part ...
- 867
-2
votes
1
answer
202
views
Natural constructions (not depending on parameters) [closed]
Consider graph clusterings as a prototypical example of (logical) constructions.
Let a clustering of a graph $(V,E)$ be any covering of $V$, i.e. a set $C$ with $\bigcup C = V$.
I am looking for a ...
- 9,720
7
votes
2
answers
851
views
Deriving Konig's Lemma directly from Infinite Ramsey's Theorem for triples
Let KL denote König's Lemma (for trees over $\mathbb{N}$), and RT(3) denote the
Infinite Ramsey Theorem for triples over $\mathbb{N}$ (notation as in Simpson's
book Subsystems of second order ...
- 205