Search Results for ""

A square matrix A such that A^2=I, where I is the identity matrix. An involutory matrix is its own matrix inverse.

The Kronecker sum is the matrix sum defined by A direct sum B=A tensor I_b+I_a tensor B, (1) where A and B are square matrices of order a and b, respectively, I_n is the ...

A method for constructing magic squares of singly even order n>=6.

The Lebesgue identity is the algebraic identity (Nagell 1951, pp. 194-195).

The portion of the complex plane z=x+iy with real part R[z]<0.

A limb of a tree at a vertex v is the union of one or more branches at v in the tree. v is then called the base of the limb.

Two or more functions, equations, or vectors f_1, f_2, ..., which are not linearly dependent, i.e., cannot be expressed in the form a_1f_1+a_2f_2+...+a_nf_n=0 with a_1, a_2, ...

A simplicial complex K is said to be locally finite if each vertex of K belongs only to finitely many simplices of K.

The unit lower half-disk is the portion of the complex plane satisfying {|z|<=1,I[z]<0}.

The portion of the complex plane {x+iy:x,y in (-infty,infty)} satisfying y=I[z]<0, i.e., {x+iy:x in (-infty,infty),y in (-infty,0)}