This contribution deals with the dominance relation on the class of conjunctors, containing as particular cases the subclasses of quasi-copulas, copulas and t-norms. The main results pertain to the summand-wise nature of the dominance relation, when applied to ordinal sum conjunctors, and to the relationship between the idempotent elements of two conjunctors involved in a dominance relationship. The results are illustrated on some well-known parametric families of t-norms and copulas.
Equiintegrability in a compact interval E may be defined as a uniform integrability property that involves both the integrand fn and the corresponding primitive Fn. The pointwise convergence of the integrands fn to some f and the equiintegrability of the functions fn together imply that f is also integrable with primitive F and that the primitives Fn converge uniformly to F. In this paper, another uniform integrability property called uniform double Lusin condition introduced in the papers E. Cabral and P. Y. Lee (2001/2002) is revisited. Under the assumption of pointwise convergence of the integrands fn, the three uniform integrability properties, namely equiintegrability and the two versions of the uniform double Lusin condition, are all equivalent. The first version of the double Lusin condition and its corresponding uniform double Lusin convergence theorem are also extended into the division space.
Early investigations on the ecology of cities were in the tradition of natural history and focused on single biotopes. Of special interest were the plants and animals introduced into newareas directly or indirectly by man. In Central Europe, studies of anthropogenic plant migrations and cultural history were combined in a specific way, the so called Thellungian paradigm. The succession of vegetation on ruins after the bombing during the Second World War was studied in many cities. Ecological studies on whole cities started in the 1970s with investigations on energy flow and nutrient cycling. Today the term urban ecology is used in two different ways: in developing programs for sustainable cities, and in investigation of living organisms in relation to their environment in towns and cities.
We consider the Robin eigenvalue problem ∆u + λu = 0 in Ω, ∂u/∂ν + αu = 0 on ∂Ω where Ω ⊂ R n , n > 2 is a bounded domain and α is a real parameter. We investigate the behavior of the eigenvalues λk(α) of this problem as functions of the parameter α. We analyze the monotonicity and convexity properties of the eigenvalues and give a variational proof of the formula for the derivative λ ′ 1 (α). Assuming that the boundary ∂Ω is of class C 2 we obtain estimates to the difference λ D k −λk(α) between the k-th eigenvalue of the Laplace operator with Dirichlet boundary condition in Ω and the corresponding Robin eigenvalue for positive values of α for every k = 1, 2, . . ..
It was shown in [7] that any right reversible, cancellative ordered semigroup can be embedded into an ordered group and as a consequence, it was shown that a commutative ordered semigroup can be embedded into an ordered group if and only if it is cancellative. In this paper we introduce the concept of $L$-maher and $R$-maher semigroups and use a technique similar to that used in [7] to show that any left reversible cancellative ordered $L$ or $R$-maher semigroup can be embedded into an ordered group.