The coverse of the Jordan Curve Theorem and a characterization of planar maps
โ Scribed by Carsten Thomassen
- Publisher
- Springer
- Year
- 1989
- Tongue
- English
- Weight
- 255 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0046-5755
No coin nor oath required. For personal study only.
โฆ Synopsis
We show that a compact set F in the plane R 2 is the union of boundaries of a map if and only if each point of F is on the boundary of at least two arcwise connected components of R2\F, and it is accessible from each of those components.
๐ SIMILAR VOLUMES
We derive a simple formula for the number of rooted loopless planar maps with a given number of edges and a given valency of the root vertex.
Let A and B be square matrices over a field F having their eigenvalues A and /z in F, and let g(x, y) = E~,s ar, xry ~ be a polynomial over F. Assuming the Jordan forms of A and B to be known, the Jordan form of E~,~ a,.~A ~ ยฎ B ~ is determined when the partial derivatives ag/dx and ag/c~y are nonze