All Questions
7 questions
2
votes
0
answers
905
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Confusing notation for sets of unordered vs ordered pairs
Given two finite sets $X$ and $Y$, one may consider the ordered pairs $(x,y)$ with $x\in X$ and $y \in Y$. Then, $(x,y) \not= (y,x)$, and $(x,x)$ exists if $x\in X$ and $x\in Y$.
One may also consider ...
- 1,444
7
votes
2
answers
247
views
complicated combinatorial algorithms with good descriptions
For educational purposes, I am looking for an example of a complicated, elementary, but very well-explained combinatorial algorithm.
Such an example might be a bijection between two easily described ...
0
votes
1
answer
651
views
Literature about most basic existence proofs in graph theory [closed]
I'm writing a MIZAR article about foundations in graph theory e.g. constructing a supergraph from a given graph by adding a vertex to it. The main theorem of the article will be that any graph ...
- 237
10
votes
1
answer
308
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In what area of study does one encounter this principle in timetabling?
A while ago I saw an image like the one below in a lecture, which was supposed to represent a rail network in a (square) city:
The circles represent trains that are moving either North/South or East/...
- 4,049
6
votes
0
answers
359
views
Have topographs been studied before?
This is my first post on MO so I hope this question is suitable. I have quite a few definitions which I will need to state before my questions at the end of this post. Please let me know if anything ...
- 661
10
votes
2
answers
962
views
Surveys of the items of Erdős' "toolbox"
Could you point out some survey papers and monographs that highlight the kernel of tricks, techniques, and tools that Paul Erdős employed the most in his research work (in particular in graph theory, ...
22
votes
5
answers
4k
views
Collection of conjectures and open problems in graph theory
Is there something similar to the Kourovka Notebook for graph theory (or anyway an organized, possibly commented, collection of conjectures and open problems)?
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