When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. 2-factor theorem - Wikipedia

    en.wikipedia.org/wiki/2-factor_theorem

    The theorem was discovered by Julius Petersen, a Danish mathematician. It is one of the first results ever discovered in the field of graph theory. The theorem appears first in the 1891 article "Die Theorie der regulären graphs". To prove the theorem, Petersen's fundamental idea was to 'colour' the edges of a trail or a path alternatively red ...

  3. Kuratowski's theorem - Wikipedia

    en.wikipedia.org/wiki/Kuratowski's_theorem

    Proof without words that a hypercube graph is non-planar using Kuratowski's or Wagner's theorems and finding either K 5 (top) or K 3,3 (bottom) subgraphs. If is a graph that contains a subgraph that is a subdivision of or ,, then is known as a Kuratowski subgraph of . [1]

  4. Graph theory - Wikipedia

    en.wikipedia.org/wiki/Graph_theory

    In set theory and graph theory, denotes the set of n-tuples of elements of , that is, ordered sequences of elements that are not necessarily distinct. In the edge ( x , y ) {\displaystyle (x,y)} directed from x {\displaystyle x} to y {\displaystyle y} , the vertices x {\displaystyle x} and y {\displaystyle y} are called the endpoints of the ...

  5. Category:Theorems in graph theory - Wikipedia

    en.wikipedia.org/wiki/Category:Theorems_in_graph...

    Pages in category "Theorems in graph theory" The following 54 pages are in this category, out of 54 total. This list may not reflect recent changes. 0–9.

  6. Second-order logic - Wikipedia

    en.wikipedia.org/wiki/Second-order_logic

    The second-order logic without these restrictions is sometimes called full second-order logic to distinguish it from the monadic version. Monadic second-order logic is particularly used in the context of Courcelle's theorem, an algorithmic meta-theorem in graph theory. The MSO theory of the complete infinite binary tree is decidable.

  7. Fleischner's theorem - Wikipedia

    en.wikipedia.org/wiki/Fleischner's_theorem

    A 2-vertex-connected graph, its square, and a Hamiltonian cycle in the square. In graph theory, a branch of mathematics, Fleischner's theorem gives a sufficient condition for a graph to contain a Hamiltonian cycle. It states that, if is a 2-vertex-connected graph, then the square of is Hamiltonian.

  8. Courcelle's theorem - Wikipedia

    en.wikipedia.org/wiki/Courcelle's_theorem

    In the study of graph algorithms, Courcelle's theorem is the statement that every graph property definable in the monadic second-order logic of graphs can be decided in linear time on graphs of bounded treewidth. [1] [2] [3] The result was first proved by Bruno Courcelle in 1990 [4] and independently rediscovered by Borie, Parker & Tovey (1992 ...

  9. Kirchhoff's theorem - Wikipedia

    en.wikipedia.org/wiki/Kirchhoff's_theorem

    In the mathematical field of graph theory, Kirchhoff's theorem or Kirchhoff's matrix tree theorem named after Gustav Kirchhoff is a theorem about the number of spanning trees in a graph, showing that this number can be computed in polynomial time from the determinant of a submatrix of the graph's Laplacian matrix; specifically, the number is equal to any cofactor of the Laplacian matrix.