Comment on “Multiphase approach to the numerical solution of a sharp interface saltwater intrusion problem” by P. S. Huyakorn, Y. S. Wu, and N. S. Park

Multiphase approach to the numerical solution of a sharp interface saltwater intrusion problem

A sharp interface numerical model is developed to simulate saltwater intrusion in multilayered coastal aquifer systems. The model takes into account the flow dynamics of salt water and fresh water assuming a sharp interface between the two liquids. In contrast to previous two-fluid flow models which were formulated using the hydraulic heads of fresh water and salt water as the dependent variabl...

Y . - N . Wu and S . - N . Wu Channels in Oral

Logical s-t Min-Cut Problem: An Extension to the Classic s-t Min-Cut Problem

Let $G$ be a weighted digraph, $s$ and $t$ be two vertices of $G$, and $t$ is reachable from $s$. The logical $s$-$t$ min-cut (LSTMC) problem states how $t$ can be made unreachable from $s$ by removal of some edges of $G$ where (a) the sum of weights of the removed edges is minimum and (b) all outgoing edges of any vertex of $G$ cannot be removed together. If we ignore the second constraint, ca...

Another Approach to Juhl ’ s Conformally Covariant Differential Operators from S n to S n −

A family (Dλ)λ∈C of differential operators on the sphere S n is constructed. The operators are conformally covariant for the action of the subgroup of conformal transformations of S which preserve the smaller sphere Sn−1 ⊂ S. The family of conformally covariant differential operators from S to Sn−1 introduced by A. Juhl is obtained by composing these operators on S and taking restrictions to Sn−1.

On the p - adic Waring ’ s problem

Let R be a ring (commutative with unity, in what follows). For an integer n > 1 define gR(n) to be the least integer s for which every element of R is a sum of s nth powers of elements of R, if such an integer exists, or ∞ otherwise. Waring’s problem for R is the problem of deciding whether gR(n) is finite and estimating it for all n. Note that what is usually called Waring’s problem is not wha...