Sums and products of intervals in ordered semigroups

We show a simple example for ordered semigroup 𝕊 = 𝕊 (+,⩽) that 𝕊 ⊆ℝ (ℝ denotes the real line) and ]a, b[ + ]c, d[ = ]a + c, b + d[ for all a, b, c, d ∈ 𝕊 such that a < b and c < d, but the intervals are no translation invariant, that is, the equation c +]a, b[ = ]c + a, c + b[ is not always fulfilled for all elements a, b, c ∈ 𝕊 such that a < b. The multiplicative version of the above example is shown too. The product of open intervals in the ordered ring of all integers (denoted by ℤ) is also investigated. Let Ix := {1, 2, . . ., x} for all x ∈ ℤ+ and defined the function g : ℤ+ → ℤ+ by g ( x ) : = max { y ∈ ℤ + | I y ⊆ I x ⋅ I x } g\left( x \right): = \max \left\{ {y \in {\mathbb{Z}_ + }|{I_y} \subseteq {I_x} \cdot {I_x}} \right\} for all x ∈ ℤ+. We give the function g implicitly using the famous Theorem of Chebishev. Finally, we formulate some questions concerning the above topics.

Absorption induced ordered ring and inner network structures on a nanoporous substrate

Liquid absorption induced the formation of a novel pattern of an ordered ring with inner networks on the nanoporous substrate.

On the Dedekind completion of function rings

This paper introduces the frame of partially defined real numbers and the lattice-ordered ring of partial real functions on a frame. This is then used to construct the order completion of rings of pointfree continuous real functions. The bounded and integer-valued cases are also analysed. The application of this pointfree approach to the classical case C(

Note on Lattice-ordered Rings with Positive Squares

Bourbaki, Birkhoff-Pierce and Fuchs pointed out or showed that a lattice-ordered field in which each square is positive must be totally ordered. Yang proved that a lattice-ordered ring R is a totally ordered skew-field if and only if every strictly positive element of R is invertible and each square in R is positive. In this note, we construct a simple example to explain the difference between order-isomorphisms and lattice-isomorphisms, and show that the difference can be dropped in lattice-ordered rings. Especially, this yields an extension and an elementary proof of the main theorem in Yang's paper.