In this article, a mathematical model to study the dynamics ofHIV-TB co-infection with two time delays is proposed and analyzed.We compute the basic reproduction number for each disease (HIV andTB) which acts as a threshold parameters. The disease dies out whenthe basic reproduction number of both diseases are less than unityand persists when the basic reproduction number of atleast one of thedisease is greater than unity. A numerical study on the model is alsoperformed to investigate the influence of certain key parameters on thespread of the disease. Mathematical analysis of our model shows thatswitching co-infection (HIV and TB) to single infection (HIV) can beachieved by imposing treatment for both the disease simultaneouslyas TB eradication is made possible with effective treatment.
We narrow in on the number of graphical partitions for which there is no known generating function by manipulating the well known generating function for Frobenius partitions.
Let gcd(a, b) = 1. J. Olsson and D. Stanton proved that the maximum number of boxes in a simultaneous (a, b)-core is (a2 −1)(b2 −1) 24, and showed that this maximum is achieved by a unique core. P. Johnson combined Ehrhart theory with the polynomial method to prove D. Armstrong's conjecture that the expected number of boxes in a simultaneous (a, b)-core is (a−1)(b−1)(a+b+1) 24. We apply P. Johnson's method to compute the variance and third moment. By extending the definitions of “simultaneous cores” and “number of boxes” to affine Weyl groups, we give uniform generalizations of these formulae to simply-laced affine types. We further explain the appearance of the number 24 using the “strange formula” of H. Freudenthal and H. de Vries.
In this paper we introduce factorial characters for the classical groups and derive a number of central results. Classically, the factorial Schur function plays a fundamental role in traditional symmetric function theory and also in Schubert polynomial theory. Here we develop a parallel theory for the classical groups, offering combinatorial definitions of the factorial characters for the symplectic and orthogonal groups, and further establish flagged factorial Jacobi-Trudi identities and factorial Tokuyama identities, providing proofs in the symplectic case. These identities are established by manipulating determinants through the use of certain recurrence relations and by using lattice paths.
In this paper, we provide a method to find a Hamiltonian cycle in the prism of a 5-chordal graph, which is $(1+ε)$-tough, with some special conditions.