What is com(M) for a matrix and what are its properties?

[Jhenrique]

"Com" of a Matrix

I was studying some topics of tensors and I found this relationship in http://fr.wikipedia.org/wiki/Tenseur_des_contraintes#Invariants_du_tenseur_des_contraintes.

I searched for com(M) but I not found nothing! What is com(M) and which are its properties?

 

[AlephZero]

If you compare the English wiki page http://en.wikipedia.org/wiki/Cauchy_stress_tensor#Principal_stresses_and_stress_invariants

I guess $\text{com}(t_{ij})$ is something related to $\frac 1 2 (t_{ii}t_{jj} - t_{ij}t_{ji})$.

But I never saw the name "com" before.

 

[Office_Shredder]

Unable to read french and not being particularly knowledgeable about the topic matter, it bothers me greatly that T_ij appears to depend on neither i nor j in the French version.

 

[Jhenrique]

I discovered what means com(A), means C(A), Cof(A), means the matrix that when is transposed is equal to Adj(A).
http://fr.wikipedia.org/wiki/Matrice_inversible#M.C3.A9thode_des_cofacteurs