

Positive Definite Matrices  Positive SemiDefinite(PSD) Matrices  
Eudclidan Distance Matrices 

Completely Positive (CP) Matrices  Doubly Nonnegative (DN) Matrices  
Strictly
Copositive 
Copositve 

MMatrices  M0Matrices  
Symmetric Mmatrices  Symmetric M0matrices  
Inverse MMatrices  Singular Inverse Mmatrices (TCIMmatrices)  
Symmetric Inverse Mmatrices  
PMatrices  P0Matrices  P0,1Matrices 
Positive (Nonnegative) Pmatrices  Nonnegative P0 (nnP0)matrices  
Sign symmetric P (ssP) Matrices  Signsymmetric P0 (ssP0) Matrices  Sign Symmetric P0,1Matrices 
Weakly sign symmetric P (wssP) Matrices  Weakly sign symmetric P0 (wssP0) Matrices  Weakly Sign Symmetric P0,1Matrices 
If the class you want is not linked, email
for information.
The onetotwo page PDF files for individual
classes
contain the following information:
Status: summary of current state of knowledge (e.g., done, little progress, etc.) Definition of the class of matrices. Definition of a partial matrix in the class Results: more detailed description of what is known, including citations to references. Examples of digraph or graph diagrams, having completion and not having completion. On the diagram, a vertex v with (v,v) included in the pattern (a specified vertex) is indicated by a solid black dot and a vertex v with (v,v) omitted from the pattern (an unspecified vertex) will be indicated by a hollow circle. For a symmetric class, only positionally symmetric patterns are relevant, and diagrams are graph diagrams; otherwise they are digraph diagrams. In a digraph, when both arcs (v,w) and (w,v) are present in a digraph, the arrows can be omitted, and this is represented by a double line. Thus for a positionally symmetric pattern for a nonsymmetric class a digraph diagram with double edges is used. References
This page is designed and maintained by Leslie Hogben with
contributions
from Luz DeAlba, Amy Wangsness, and Shaun Fallat.
Please email any corrections, suggestions or contributions to lhogben@iastate.edu