Let f be an analytic function on the plane and A a square matrix of order n whose eigenvalues are contained in the interior of a circle K centered at the origin. The expression f(A) = fKf(z)(z-A)-dz has been widely used to calculate (or define) the value of f at A. A special case of this formula provides us with a trivial proof of the Cayley-Hamilton theorem. We need only the most elementary no...

We show a novel lattice-based scheme (PairTRU) which is a non-commutative variant of the NTRU. The original NTRU is defined via the ring of quotient with variable in integers and this system works in the ring R = Z[x] . We extend this system over Z× Z and it performs all of operations in the non-commutative ring M = M(k,Z×Z)[x] <(Ik×k,Ik×k)x−(Ik×k,Ik×k)> , where M is a matrix ring of k ×...

We notice that there is a 2-cover P of S 1 SO(3) (we denote this group D 1/2 ) by the group U(2): P sends a matrix z into a pair (det z,v). The matrix v here is the image of u under a standard covering map p from SU(2) onto SO(3), see (3.4) below. Finally, u (being a matrix from SU(2) ) is determined (up to a sign) from the decomposition z = du, here d 2 = det z. Both P and p are group homomorp...

1. Unitary Geometry on Exceptional Cartan Domains In 1935, E.Cartan classified all symmetric bounded domains. He prived that there exit only six types of irreducible bounded symmetric domains in C. They can be realized as follows: RI(m,n) = {Z ∈ Cmn|I − ZZ ′ > 0, Z − (m,n) matrix} RIIp = {Z ∈ Cp(p+1)/2|I − ZZ ′ > 0, Z − symmetric matric of degree p} RIIIq = {Z ∈ Cq(q−1)/2|I − ZZ ′ > 0, Z − skew...

Let P be an r×smatrix of Laurent polynomials with symmetry such that P(z)P∗(z) = Ir for all z ∈ C\{0} and the symmetry of P is compatible. The matrix extension problem with symmetry is to find an s × s square matrix Pe of Laurent polynomials with symmetry such that [Ir,0]Pe = P (that is, the submatrix of the first r rows of Pe is the given matrix P), Pe is paraunitary satisfying Pe(z)Pe(z) = Is...

We consider the first-order Cauchy problem ∂zu + a(z, x,Dx)u = 0, 0 < z ≤ Z, u |z=0 = u0, with Z > 0 and a(z, x,Dx) a k×k matrix of pseudodifferential operators of order one, whose principal part a1 is assumed symmetrizable: there exists L(z, x, ξ) of order 0, invertible, such that a1(z, x, ξ) = L(z, x, ξ) (−iβ1(z, x, ξ) + γ1(z, x, ξ)) (L(z, x, ξ))−1, where β1 and γ1 are hermitian symmetric and...

It is well-known that a connected regular graph is strongly-regular if and only if its adjacency matrix has exactly three eigenvalues. Let B denote an integral square matrix and 〈B〉 denote the subring of the full matrix ring generated by B. Then 〈B〉 is a free Z-module of finite rank, which guarantees that there are only finitely many ideals of 〈B〉 with given finite index. Thus, the formal Diric...

The well-known canonical coherent states are expressed as an infinite series in powers of a complex number z and a positive sequence of real numbers ρ(m) = m!. In this article, in analogy with the canonical coherent states, we present a class of vector coherent states by replacing the complex variable z by a real Clifford matrix. We also present another class of vector coherent states by simult...

This paper examines the relationship between the dynamics of large networks and of their smaller factor-networks (factors) obtained through the factorization of the network's graph representation. We speci cally examine dynamics of networks which have Z-matrix state matrices. We perform a Cartesian product decomposition on its network structure producing factors which also have Z-matrix dynamic...

In this paper, the maximal dissipative extensions of a symmetric singular 1D discrete Hamiltonian operator with maximal deficiency indices (2,2) (in limit-circle cases at ±∞) and acting in the Hilbert space ℓ_{Ω}²(Z;C²) (Z:={0,±1,±2,...}) are considered. We consider two classes dissipative operators with separated boundary conditions both at -∞ and ∞. For each of these cases we establish a self...