Space Form Research Articles

Ricci curvature for biwarped product submanifolds of the type N𝜃1 ×f2N𝜃2 ×f3N𝜃3 in Kenmotsu space forms

The major goal of this work is to express the Ricci curvature inequality for biwarped product submanifold of the type [Formula: see text] isometrically immersed in a Kenmotsu space form via terms of the squared norm of mean curvature vector and warping functions, where [Formula: see text], [Formula: see text] and [Formula: see text] are the slant submanifolds with slant angles [Formula: see text], [Formula: see text] and [Formula: see text]. The interpretations of equality are also explored. In addition, we provide several applications of these inequalities.

K-Hessian curvature type equations in space forms

In this article, we study closed star-shaped (eta, k)-convex hypersurfaces in space forms satisfying a class of k-Hessian curvature type equations. Firstly, using the maximum principle, we obtain a priori estimates for the class of Hessian curvature type equations. Secondly, we obtain an existence result by using standard degree theory based on a priori estimates.

The recovery of protest in Japan: from the ‘ice age’ to the post-2011 movements

ABSTRACT For a long time after the end of large-scale student unrest in the 1970s Japan stood out by a comparatively low level of protest. Yet spectacular waves of mass-protest returned with the anti-nuke mobilizations following the 2011 Fukushima meltdown and other ‘post-2011’ movements. In this paper I develop an analytical framework inspired by the multi-level perspective in transition studies to illuminate two questions: how can the relatively low level of protest in Japan before 2011 – in particular the so called ‘ice age’ of protest from the 1970s to the early 2000s – be explained, and what enabled the recovery of protest afterwards, starting in the early 2000s and leading up to the post-2011 protest cycle? I point to the crucial role played on the one hand by niches in the form of social movement spaces in fostering oppositional discourses and on the other hand by landscape changes that destabilized the established politico-cultural regime. A crucial role was played by the creative work of freeter activists in social movement spaces during the 1990s who reinvented activism in response to stigmatization of open protest after the collective trauma of the perceived defeat of the New Left in the 1970s. This creative work was a precondition for the rise of protest movements in the early 2000s which in turn prepared the way for the post-2011 protest wave.

Welcoming Immigrants

Problem, research strategy, and findings Few studies have systematically examined the role of municipal planning in creating immigrant-friendly cities despite the importance of immigration to the growth and development of cities. In this research project I asked to what extent and how planners are involved in immigrant welcoming initiatives. The interviews draw from two perspectives—planning and immigrant affairs—through content analysis of 42 interviews in 30 “welcoming” cities, 28 comprehensive plans, and 17 immigrant integration plans. The analysis revealed that planners are not very engaged with welcoming initiatives or immigrant affairs staff. Planners tinker with land use regulations to accommodate immigrants in specific contexts and are looking for ways to do better outreach. Overall, planning continues as “business as usual” in cities calling themselves welcoming to immigrants. Surprisingly, immigrant affairs staff and planners know little about each other. Takeaway for practice Planners provide the ability to think spatially and long term about the rules governing the form and function of urban spaces. Immigrant affairs officials offer in-depth knowledge about the day-to-day struggles of immigrants. Together, planning and immigrant affairs have many shared goals, such as improving engagement with immigrants, helping immigrants navigate the regulatory environment in cities, and creating culturally sensitive and reasonable accommodation.

Generalized Wintgen inequality for BI-SLANT submanifolds in conformal Sasakian space form with quarter-symmetric connection

PurposeIn 1979, P. Wintgen obtained a basic relationship between the extrinsic normal curvature the intrinsic Gauss curvature, and squared mean curvature of any surface in a Euclidean 4-space with the equality holding if and only if the curvature ellipse is a circle. In 1999, P. J. De Smet, F. Dillen, L. Verstraelen and L. Vrancken gave a conjecture of Wintgen inequality, named as the DDVV-conjecture, for general Riemannian submanifolds in real space forms. Later on, this conjecture was proven to be true by Z. Lu and by Ge and Z. Tang independently. Since then, the study of Wintgen’s inequalities and Wintgen ideal submanifolds has attracted many researchers, and a lot of interesting results have been found during the last 15 years. The main purpose of this paper is to extend this conjecture of Wintgen inequality for bi-slant submanifold in conformal Sasakian space form endowed with a quarter symmetric metric connection.Design/methodology/approachThe authors used standard technique for obtaining generalized Wintgen inequality for bi-slant submanifold in conformal Sasakian space form endowed with a quarter symmetric metric connection.FindingsThe authors establish the generalized Wintgen inequality for bi-slant submanifold in conformal Sasakian space form endowed with a quarter symmetric metric connection, and also find conditions under which the equality holds. Some particular cases are also stated.Originality/valueThe research may be a challenge for new developments focused on new relationships in terms of various invariants, for different types of submanifolds in that ambient space with several connections.

Application of Traditional Architectural Decoration Elements in Modern Interior Design Based on 3D Virtual Imaging

China’s long history has produced magnificent culture, and Chinese traditional architecture, as a separate development system, has a long history and distinct style. With the gradual rise of “modern Chinese style” in recent years, architects have been constantly exploring and excavating the rich in humanistic connotation residential space form of traditional folk houses in order to adapt it to the contemporary residential life mode. Human civilization is accompanied by living behavior, and the ideal of living environment is destined to evolve in tandem with human civilization. In recent months, more and more 3D virtual technologies, such as e-commerce, interactive communities, and web games, have appeared in the Internet and construction industry as a result of the advancement of modern network technology. People are attempting to rely on computer networks and virtual reality technology to create a more diverse space environment and enjoy the virtual world’s colorful visual feast. The study of how to quickly construct a 3D scene has proven to be very fruitful.

Yaw Stability Analysis of a Tractor Semitrailer Using Yaw Plane Model

Lateral dynamics of a road vehicle refers to its directional control and stability. Bicycle model is the classical proven model for this study. This paper presents a4 degrees of freedom mathematical model, representing a three-axle tractor semitrailer, to investigate its yaw stability in combined cornering and braking manoeuvres. The equations of motion governing the system are derived using Newtonian mechanics and then converted into a state space form for simulation. A non-linear tire model and a load transfer model are implemented to accurately incorporate the effect of braking on yaw stability. In the first step, steady state analysis is performed to determine the variation of steady state gain characteristics such as yaw velocity gain and articulation angle gain for different loading conditions of the vehicle. Yaw response characteristics such as articulation angle, articulation rate, lateral velocity and yaw rate are simulated in MATLAB. In the second step, the directional responses of the vehicle during jackknifing and trailer swing are studied by performing simulations under wheel lock-up condition on different axles and are compared with the no-wheel-lock up condition. Eigen value analysis is used to observe the variation in stability under different simulation conditions. Finally in the third step the effect of increasing forward speed on the stability is also simulated.

Fractal Design of Indoor and Outdoor Forms of Architectural Space Based on a Three-Dimensional Box Dimension Algorithm

The three-dimensional organic growth features of buildings have been given more and more attention according to the unique view representation regulations of the indoor construction industry, in order to optimize the usage and allocation efficiency of building space. To explore the configuration structure of building function space, the three-dimensional box dimension algorithm is used to measure the fractal dimension of the indoor and outdoor form of building space, and the two-dimensional and three-dimensional fractal characteristics of building space are compared and analyzed; the method of the second derivative is utilized for the automatic recognition of fractal scale-free areas, aiming at the imprecise problem of the artificial judgment of scale-free areas in earlier fractal research of interior and outdoor forms of architectural space. The experimental results show that the second derivative method can effectively and automatically identify the scale-free region. The coefficients of linear fitting are above 0.990, and the indoor and outdoor forms of architectural space have clear fractal characteristics. After applying the method, the three-dimensional fractal dimension grows, indicating that the interior and outdoor form usage of architectural space in this area is generally effective and compact.

Four-dimensional steady gradient Ricci solitons with 3-cylindrical tangent flows at infinity

In this paper we consider 4-dimensional steady soliton singularity models, i.e., complete steady gradient Ricci solitons that arise as the rescaled limit of a finite time singular solution of the Ricci flow on a closed 4-manifold. In particular, we study the geometry at infinity of such Ricci solitons under the assumption that their tangent flow at infinity is the product of R with a 3-dimensional spherical space form. We also classify the tangent flows at infinity of 4-dimensional steady soliton singularity models in general.

Spatial Planning as Public Space: Some Issues of Local Democracy raised by the Extension of the École hôtelière in the Lausanne peri-urban area

Abstract Based on a field survey on the conflicts regarding the extension of the Ecole Hôtelière de Lausanne, this text discusses the production of public space. These controversies make possible an understanding of the production process of peri-urban space in terms of residential aspirations and negotiation mechanisms. This investigation allows us to understand the articulation of the two forms of public space – as publicity and as a set of freely accessible places – and the questions of local democracies related to them.

The Immanent Infinite

The Immanent Infinite

Research on the Plane Spatial Form of Economic Housing Based on Space Syntax Theory: Macau EDF. de Alameda da Tranquilidade as an Example

Since the reform and opening up, the city has steadily promoted the renovation of old maternity houses, towns and villages in response to the call of the state, thus promoting urban renewal, realizing urban economic development, industrial upgrading and people's livelihood improvement. The living density of economic housing is high, and the quality needs to be further optimized. However, the current urban renewal needs to improve the living quality of housing to serve the people. Therefore, when planning, constructing and renovating the interior space of public housing and meeting people's basic living conditions, people's intuitive feeling of the environment should be put first, rather than excessive attention to formal beauty—taking the EDF. de Alameda da Tranquilidade in Macau, as an example, based on the theory of space syntax, this paper conducts a convex space analysis and research on the interior space form of the first building of EDF. de Alameda da Tranqui-lidade, including the global integration degree, local integration degree (R=3,6), connectivity, intelligibility, control and Mean Depth, analyze the areas with higher integration, connection value and control value and lower areas, and make suggestions for future plane optimization, related The recommendations also apply to the second and third buildings of Yongning Plaza Building, providing better reference value and reference for relevant government departments.

Study on ecological adaptability of traditional village construction in Hainan volcanic areas

In this study, 112 traditional villages in volcanic areas of Hainan Province were investigated. The field investigation, spatial analysis, statistics and comparative study on the traditional villages and vernacular dwellings in Hainan volcanic areas were performed. Based on the theory of ecological adaptability, the layout of traditional villages and the types, distribution and differences of vernacular dwellings in Hainan volcanic areas were studied from the perspective of village layout structure, architectural space form and construction mode. It is found that the natural environment, architectural functions, customs, national culture and other aspects are the fundamental reasons for the formation and differences of buildings. The ecological adaptation process of traditional villages includes not only the adaptation of external topography, climate conditions and natural resources, but also the ecological adaptation of internal built environment. Meanwhile, the evolution of traditional villages is closely related to social-ecological adaptation. In addition, the ecological concept and technical experience of the traditional villages in Hainan volcanic areas in adapting to the natural environment and social environment were summarized. This study provides a reference for the protection and renewal of cultural landscape in Hainan volcanic areas.

On 2-Stein Submanifolds in Space Forms

We prove that a 2-stein submanifold in a space form whose normal connection is flat or whose codimension is at most 2, has constant curvature.

Sharp Simons type integral inequalities for closed linear Weingarten submanifolds in a space form

Sharp Simons type integral inequalities for closed linear Weingarten submanifolds in a space form

Community repair in the circular economy – fixing more than stuff

ABSTRACT In the circular economy discourse it is stressed that products ought to be repairable and that repair work is assumed to be growing. However, repair can be organised and performed in different ways – by corporate entities, independent repairers, laypersons and communities. Some corporations are integrating repair and maintenance into their offering, while simultaneously restricting consumers to open, repair or modify their products. In opposition to such developments, there is a movement for “right to repair”, which works for consumers’ legal rights to repair and modify products, pushing for the free availability of spare parts and manuals. Recent years have also seen a growth of repair cafés and other forms of DIY community repair spaces. This paper explores the discourses of DIY community repair through two Swedish case studies – an NGO-led nationwide repair campaign and a local government initiative of open DIY repair spaces. Our case studies show how DIY community repair works towards enabling all, particularly marginalised groups, to participate and live well in a low-impact future. In contrast to the mainstream circular economy discourse, the purpose of community repair is not only about repairing broken stuff and reducing waste, but about building social relations and practicing non-consumerist forms of citizenship. By elucidating these different perspectives on repair – who is to perform it, with what skills and for what purposes – we highlight how the transition to future, more circular economies, can be enacted and steered in ways that allow for different roles and powers for citizen-consumers.

Kähler–Ricci solitons induced by infinite-dimensional complex space forms

We exhibit families of non trivial (i.e. not Kaehler-Einstein) radial Kaehler-Ricci solitons (KRS), both complete and not complete, which can be Kaehler immersed into infinite dimensional complex space forms. This result shows that the triviality of a KRS induced by a finite dimensional complex space form proved in [12] does not hold when the ambient space is allowed to be infinite dimensional. Moreover, we show that the radial potential of a radial KRS induced by a non-elliptic complex space form is necessarily defined at the origin.

Cellularization for exceptional spherical space forms and the flag manifold of [formula omitted

We construct an explicit equivariant cellular decomposition of the (4n−1)-sphere with respect to binary polyhedral groups, and describe the associated cellular chain complex. As a corollary of the binary octahedral case, we deduce an S3-equivariant decomposition of the flag manifold of SL3(R).

New Characterizations of the Whitney Spheres and the Contact Whitney Spheres

In this paper, based on the classical Yano’s formula, we first establish an optimal integral inequality for compact Lagrangian submanifolds in the complex space forms, which involves the Ricci curvature in the direction \(J\mathbf {H}\) and the norm of the covariant differentiation of the second fundamental form h, where J is the almost complex structure and \(\mathbf {H}\) is the mean curvature vector field. Second and analogously, for compact Legendrian submanifolds in the Sasakian space forms with Sasakian structure \((\varphi ,\xi ,\eta ,g)\), we also establish an optimal integral inequality involving the Ricci curvature in the direction \(\varphi \mathbf {H}\) and the norm of the modified covariant differentiation of the second fundamental form. The integral inequality is optimal in the sense that all submanifolds attaining the equality are completely classified. As direct consequences, we obtain new and global characterizations for the Whitney spheres in complex space forms as well as the contact Whitney spheres in Sasakian space forms. Finally, we show that, just as the Whitney spheres in complex space forms, the contact Whitney spheres in Sasakian space forms are locally conformally flat manifolds with sectional curvatures non-constant.

Between the city and the sea: the welfare landscape of Køge Bay seaside park and the urbanization of nature in post-war Denmark

This article is published as part of the Geografiska Annaler: Series B, Human Geography special issue ‘Revisiting the Green Geographies of Welfare Planning’, edited by Johan Pries & Mattias Qviström. ABSTRACT This article uses Køge Bay Seaside Park as a case to explore the relations between welfare planning, landscapes and the urbanization of nature in 1970s and 1980s Denmark. In recent years, scholars have increasingly pointed to the constitutive role of green spaces and recreational landscapes in the realization of the Nordic welfare model. Until now, this research has mainly concentrated on green spaces in the form of forests, parks and open green spaces on housing estates. Yet, as this article demonstrates, Danish welfare planning also involved the creation of new city-sea geographies that spatialized the welfare society as an everyday experience. More specifically, Køge Bay Seaside Park exhibits the instrumental role of landscapes the making of Danish welfare urbanism. To demonstrate this, the article draws attention to the multiple and extensive ways in which the seaside park’s landscape rested upon and entailed the urbanization of nature. Focusing on water, the article examines how such processes unfolded through multiple scales and layers of the landscape. In the seaside park, water appeared in many different forms – as bathing water, wastewater, potential floods and as a representation of physical and social well-being – and were formative in the production of new city-sea relations and welfare lifestyles.