This article explores the concept of metaphysically opaque grounding, a largely neglected form of metaphysical grounding that challenges the commonly held assumptions that grounding is an especially intimate and powerful connection between facts and that it is necessarily connected with the essences of things. I provide a definition of opaque grounding, identify some interesting philosophical views that are committed to it, and explore some consequences for the general theory of grounding. Finally, I briefly address some natural initial doubts about opaque grounding and find them unwarranted. The upshot is that the notion deserves more attention than it has previously received.

Let W be a 2-dimensional Coxeter group, that is, one with 1/mst + 1/msr + 1/mtr ≤ 1 for all triples of distinct s, t, r ∈ S. We prove that W is biautomatic. We do it by showing that a natural geodesic language is regular (for arbitrary W), and satisfies the fellow traveller property. As a consequence, by the work of Jacek Świątkowski, groups acting properly and cocompactly on buildings of type W are also biautomatic. We also show that the fellow traveller property for the natural language fails for $W=\widetilde {A}_3$.

This article aims to provide an explication of the doctrine of the monarchy of the Father. A precisification of the doctrine is made within the building-fundamentality framework provided by Karen Bennett, which enables a further clarification of the central elements of the doctrine to be made and an important objection against it to be answered.

A Tits polygon is a bipartite graph in which the neighborhood of every vertex is endowed with an “opposition relation” satisfying certain properties. Moufang polygons are precisely the Tits polygons in which these opposition relations are all trivial. There is a standard construction that produces a Tits polygon whose opposition relations are not all trivial from an arbitrary pair $(\unicode[STIX]{x1D6E5},T)$, where $\unicode[STIX]{x1D6E5}$ is a building of type $\unicode[STIX]{x1D6F1}$, $\unicode[STIX]{x1D6F1}$ is a spherical, irreducible Coxeter diagram of rank at least $3$, and $T$ is a Tits index of absolute type $\unicode[STIX]{x1D6F1}$ and relative rank $2$. A Tits polygon is called $k$-plump if its opposition relations satisfy a mild condition that is satisfied by all Tits triangles coming from a pair $(\unicode[STIX]{x1D6E5},T)$ such that every panel of $\unicode[STIX]{x1D6E5}$ has at least $k+1$ chambers. We show that a $5$-plump Tits triangle is parametrized and uniquely determined by a ring $R$ that is alternative and of stable rank $2$. We use the connection between Tits triangles and the theory of Veldkamp planes as developed by Veldkamp and Faulkner to show existence.

We prove simplicity for incomplete rank 2 Kac—Moody groups over algebraic closures of finite fields with trivial commutation relations between root groups corresponding to prenilpotent pairs. We don't use the (yet unknown) simplicity of the corresponding finitely generated groups (i.e., when the ground field is finite). Nevertheless we use the fact that the latter groups are just infinite (modulo center).

Vibrations in buildings impact the behaviour of structures and humans, for sourcesdefined as internal or external to the building. Besides the comparison of vibrations tofixed limits, the choice of a relevant indicator is unavoidable and this indicator isdefined differently according to the selected reference text. Various standards (ordirectives similar to standards) exist and this paper focuses on the most important andthe most used ones, for ground vibrations induced to buildings or for human exposureinside buildings. In addition to the interest of comparing values to well-defined andwell-known limits, the knowledge of these standards allows the use of suitable indicators.Various vibration signals are used, from a simple harmonic signal to complex vibrationsgenerated by railway traffic, in order to present a relevant analysis of severity of eachnorm. It turns out that criteria noticeably vary from one reference to another one, andthat the thresholds are different for each standard.

The gamma-ray exposure build-up factors of raw materialsof bricks (soils and fly-ashes) in the state of Punjab were investigatedfor the photon energy range 0.015 to 15 MeV up to 40 mfp penetrationdepth by the geometrical progression (GP) method. Appreciable variationsin the exposure build-up factor (EBF) are noted for the raw materials.The EBFs of the raw materials of bricks change depending on thephoton energy, penetration depth and chemical composition. The build-up factorsare low at low and high photon energies, whereas they are very highin the medium-energy region. The peak energy of the EBF for soilsis 0.3 MeV and 0.2 MeV for fly ashes. The EBFs of the raw materialsof bricks are also compared with those of bricks of red mud andcommon brick materials. Common bricks were found to have the lowestgamma-ray EBF. This study should be useful for emergency preparednessplanning and emergency dose estimation for future planned nuclearpower plants in the state of Punjab.

Recently, there has been a lot of interest concerning remote-controlled robot manipulation in hazardous environments including construction sites, national defense areas, and disaster areas. However, there are problems involving the method of remote control in unstructured work environments such as construction sites. In a previous study, to address these problems, a multipurpose field robot (MFR) system was described. Though the case studies on construction, to which “MFR for installing construction materials” was applied, however, we found some factors to be improved. In this paper, we introduce a prototype of improved multipurpose field robot (IMFR) for construction work. This prototype robot helps a human operator easily install construction materials in remote sites through an upgraded additional module. This module consists of a force feedback joystick and a monitoring device. The human–robot interaction and bilateral communication for strategic control is also described. To evaluate the proposed IMFR, the installation of construction materials was simulated. We simulated the process of installing construction materials, in this case a glass panel. The IMFR was expected to do more accurate work, safely, at construction sites as well as at environmentally hazardous areas that are difficult for humans to approach.

Given a complete $\text{CAT}(0)$ space $X$ endowed with a geometric action of a group $\Gamma $, it is known that if $\Gamma $ contains a free abelian group of rank $n$, then $X$ contains a geometric flat of dimension $n$. We prove the converse of this statement in the special case where $X$ is a convex subcomplex of the $\text{CAT}(0)$ realization of a Coxeter group $W$, and $\Gamma $ is a subgroup of $W$. In particular a convex cocompact subgroup of a Coxeter group is Gromov-hyperbolic if and only if it does not contain a free abelian group of rank 2. Our result also provides an explicit control on geometric flats in the $\text{CAT}(0)$ realization of arbitrary Tits buildings.

Robot intensiveness in the manufacturing industry is growing rapidly, but the construction industry has been slow to capitalise on the array of robotic technology now available. An attempt is made to indentify various robot ensembles that may prove economically viable in building construction, and to configure these in such a way that particular characteristics of robot work methods are used to maximum advantage within the constraints of the construction environment.

This paper presents a review of CBD and its application to building design in particular. Case-based design is the application of case-based reasoning to the design process. Design maps well to case-based reasoning because designers use parts of previous design solutions in developing new design solutions. This paper identifies problems of case representation, retrieval, adaptation, presentation, and case-based maintenance along with creativity, legal, and ethical issues that need to be addressed by CBD systems. It provides a comprehensive review of CBD systems developed for building design and provides a detailed comparison of the CBD systems reviewed.

If G is a (split) Kac–Moody group over a field K endowed with a real valuation $\omega$, we build an action of G on a geometric object $\mathcal I$. This object is called a building, as it is an union of apartments, with the classical properties of systems of apartments. However, these apartments are more exotic: that associated to a torus T may be seen as the gluing of all Satake compactifications of affine apartments of T with respect to spherical parabolic subgroups of G containing T. Another geometric realization of these apartments makes them look more like the apartments of $\Lambda$-buildings; then the translations of the Weyl group act only on infinitely small elements of the apartment, so we call these buildings microaffine.