Inverse positive matrix

A symmetric Z-matrix has a positive inverse if and only if it has a positive definite inverse.

http://books.google.com/books?id=ngUgEYQAvukC&pg=PA45&lpg=PA45&dq=positive+definite+Z-matrix+inverse+positive&source=bl&ots=joJYO0yAD3&sig=Tfurzf9Tn7LX6RtyDyTF94g7kDs&hl=ko&sa=X&ei=3mboTtSxNoqsiQLB64TaAg&ved=0CEIQ6AEwAw#v=onepage&q=positive%20definite%20Z-matrix%20inverse%20positive&f=false

 

Hawkins-Simon condition

Le Chatelier-Braun principle

 

http://en.wikipedia.org/wiki/Le_Chatelier's_principle

 

http://www.emis.ams.org/journals/ELA/ela-articles/articles/vol11_pp59-65.pdf

 

http://dml.cz/dmlcz/100526

 

 

 

http://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/30645/1/3_P46-48.pdf]]