Invariants and Operations - GraphFilter/GraphFilter GitHub Wiki

Invariants

Invariants are graph properties that depends only on the abstract structure, not on particular labeling or drawings of the graph. Examples include the number of vertices and the number of edges. Here we list all the graph operations and invariants already inserted in the project, with the respective library used for implementation.

Numeric Invariants

They can be used in the writing of (in)equations or after filtering, to study the output graphs.

Structural

Chromatic number (χ) Matching number (ν) Radius (r)
Number of vertices (n) Number of components (w) Vertex connectivity (ϰ)
Number of edges (Е) Degree regularity (dᵣ) Edge connectivity (λ)
Clique number (ω) Maximum degree (Δ) Minimum edge cover number (mec)
Independence number (⍺) Minimum degree (ẟ) Number of triangles (Τ)
Total domination number (Ɣₜ) Average degree (dₐ) Wiener Index (W)
Domination number (Ɣ) Vertex cover number (τ) Number of Spanning trees (ʈ)
Girth (ɡ) Diameter (diam) Density (Ɗ)
Spectral
Largest M-eigenvalue

M=A, L, Q, N, S, D, DL, DQ, E
2th Largest M-eigenvalue

M=A, L, Q, N, S, D, DL, DQ, E
Smallest M-Eigenvalue

M=A, Q, N, S, D, DL, DQ, E
M-Energy

M=A, L, Q, N, S, D, DL, DQ, E
Algebraic connectivity (ac) Estrada Index (EE)
Nullity (η) Number main M-eigenvalue

M=A, D, Q, S
Rank M- matrix

M=A, L, Q, D, N
Determinant M

M=A, L, Q, N, S, D, DL, DQ, E

The definition of M matrices can be found in Dictionary Matrix M.

To build the in(equations) the user can calculate the numeric invariants not only in the graph, but can also use the line graph and complement

Boolean Invariants

They can be used in the conditions or after filtering, to study the output graphs.

Structural
Planar Regular Connected Triangle-free
Biconnected Tree Bipartite Bull-free
Self-complementary Eulerian Regular Transmission Claw-free
Chordal Has bridge Is threshold Cubic
Spectral *
Some M-eigenvalue integer

M=A, L, Q, S, N, D, DL or DQ
M-integral

M=A, L, Q, N, S, D, DL, DQ, E
Largest M-eigenvalue is integer

M=A, L, Q, N, S, D, DL, DQ, E
Matrix M is invertible

M=A, L, Q, N, S, D, E

Other Invariants

They are invariants that are neither numeric nor boolean, but can be used to study the graphs returned in the filtering.

Structural
Dominating Set Eigenvector Centrality
Maximum Clique Closeness Centrality
Minimum edge cover (set) Betweeness Centrality
Maximum Matching Set Harmonic Centrality
Maximum Independent Set Transmission
Spectral *
Spectrum M

M= A, L, Q, N, D, S, DL, DQ, E
M-Matrix

M= A, I, L, Q, N, D, S, DL, DQ, E
Eigenvectors

M= A, L, Q, N, D, S, DL, DQ, E

Operations

Math Operations

You can also use several usual functions in mathematics:

Trigonometric Basic Functions Utils Logic Constants Symbols
Sine Sum Natural Logarithm Floor AND PI Equal
Cosine Subtraction Logarithm Ceiling OR Different
Tangent Division Square Root Modulus Less Than
Product Modulus Greater Than
Power Less or Equal Than
Greater or Equal Than

Graph Operations

These are basic operations that are applied to a single graph and return another graph.

Graph Operations
Complementary Graph Line Graph
Clique Maximal Graph

Where the matrix M can be:
  • A: Adjacency
  • L: Laplacian
  • Q: Signless Laplacian
  • N: Normalized Laplacian
  • D: Distance
  • DL: Distance Laplacian
  • DQ: Distance Signless Laplacian
  • S: Seidel
  • E: Eccentricity

The definitions is available on Dictionary Matrix M.

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