We define the total weak discrepancy of a poset P as the minimum nonnegative integer k for which there exists a function f : V → Z satisfying (i) if a ≺ b then f(a) + 1 ≤ f(b) and (ii) ∑ |f(a)− f(b)| ≤ k, where the sum is taken over all unordered pairs {a, b} of incomparable elements. If we allow k and f to take real values, we call the minimum k the fractional total weak discrepancy of P . The...

This paper constructs a logic of soft constraints where the set of degrees of preference forms a partially ordered set. When the partially ordered set is a distributive lattice, this reduces to the idempotent semiring-based CSP approach, and the lattice operations can be used to define a sound and complete proof theory. For the general case, it is shown how sound and complete deduction can be p...

R. Redheffer described an n×n matrix of 0’s and 1’s the size of whose determinant is connected to the Riemann Hypothesis. We describe the permutations that contribute to its determinant and its permanent in terms of integer factorizations. We generalize the Redheffer matrix to finite posets that have a 0 element and find the analogous results in the more general situation.

In this paper we introduce the notion of the fractional weak discrepancy of a poset, building on previous work on weak discrepancy in [5, 8, 9]. The fractional weak discrepancy wdF (P ) of a poset P = (V,≺) is the minimum nonnegative k for which there exists a function f : V → R satisfying (1) if a ≺ b then f(a) + 1 ≤ f(b) and (2) if a ‖ b then |f(a)− f(b)| ≤ k. We formulate the fractional weak...

Let L denote a set of additive hereditary graph properties. It is a known fact that a partially ordered set (La,⊆) is a complete distributive lattice. We present results when a join of two additive hereditary graph properties in (La,⊆) has a finite or infinite family of minimal forbidden subgraphs.