中国城市绿地建设已进入量质并重的时期。评估工具是管控绿地质量的一种重要手段。首先梳理英国城市绿地质量评估工具开发的缘起与主要评估工具,其次解析英国国家级评估工具绿色旗帜奖(Green Flag Award,GFA)的开发目标、质量标准、发...中国城市绿地建设已进入量质并重的时期。评估工具是管控绿地质量的一种重要手段。首先梳理英国城市绿地质量评估工具开发的缘起与主要评估工具,其次解析英国国家级评估工具绿色旗帜奖(Green Flag Award,GFA)的开发目标、质量标准、发展演进、配套政策与使用方法,再次以爱丁堡为例,总结GFA的在地化应用与实效,最后总结GFA在开发与应用方面的启示与不足以供借鉴。展开更多
The geometric characterization and structure of Finsler manifolds with constant flag curvature (CFC) are studied. It is proved that a Finsler space has constant flag curvature 1 (resp. 0) if and only if the Ricci curv...The geometric characterization and structure of Finsler manifolds with constant flag curvature (CFC) are studied. It is proved that a Finsler space has constant flag curvature 1 (resp. 0) if and only if the Ricci curvature along the Hilbert form on the projective sphere bundle attains identically its maximum (resp. Ricci scalar). The horizontal distribution H of this bundle is integrable if and only if M has zero flag curvature. When a Finsler space has CFC, Hilbert form’s orthogonal complement in the horizontal distribution is also integrable. Moreover, the minimality of its foliations is equivalent to given Finsler space being Riemannian, and its first normal space is vertical.展开更多
Though the theory of one-parameter Triebel-Lizorkin and Besov spaces has been very well developed in the past decades, the multi-parameter counterpart of such a theory is still absent. The main purpose of this paper i...Though the theory of one-parameter Triebel-Lizorkin and Besov spaces has been very well developed in the past decades, the multi-parameter counterpart of such a theory is still absent. The main purpose of this paper is to develop a theory of multi-parameter Triebel-Lizorkin and Besov spaces using the discrete Littlewood-Paley-Stein analysis in the setting of implicit multi-parameter structure. It is motivated by the recent work of Han and Lu in which they established a satisfactory theory of multi-parameter Littlewood-Paley-Stein analysis and Hardy spaces associated with the flag singular integral operators studied by Muller-Ricci-Stein and Nagel-Ricci-Stein. We also prove the boundedness of flag singular integral operators on Triebel-Lizorkin space and Besov space. Our methods here can be applied to develop easily the theory of multi-parameter Triebel-Lizorkin and Besov spaces in the pure product setting.展开更多
文摘中国城市绿地建设已进入量质并重的时期。评估工具是管控绿地质量的一种重要手段。首先梳理英国城市绿地质量评估工具开发的缘起与主要评估工具,其次解析英国国家级评估工具绿色旗帜奖(Green Flag Award,GFA)的开发目标、质量标准、发展演进、配套政策与使用方法,再次以爱丁堡为例,总结GFA的在地化应用与实效,最后总结GFA在开发与应用方面的启示与不足以供借鉴。
文摘The geometric characterization and structure of Finsler manifolds with constant flag curvature (CFC) are studied. It is proved that a Finsler space has constant flag curvature 1 (resp. 0) if and only if the Ricci curvature along the Hilbert form on the projective sphere bundle attains identically its maximum (resp. Ricci scalar). The horizontal distribution H of this bundle is integrable if and only if M has zero flag curvature. When a Finsler space has CFC, Hilbert form’s orthogonal complement in the horizontal distribution is also integrable. Moreover, the minimality of its foliations is equivalent to given Finsler space being Riemannian, and its first normal space is vertical.
基金supported by NSFC(No.11471246)Natural Science Foundation of Anhui Province(No.1608085MA03)Natural Science Foundation of Higher Education in Anhui Province(No.KJ2014A257)
基金supported partly by NSF of China (No. 10571015)SRFDP of China (No. 20050027025)+2 种基金supported by the U.S. NSF (Grant DMS No. 0500853)supported partly by NSF of China (No. 10771054)supported by NSF of China (No, 10811120558)
文摘Though the theory of one-parameter Triebel-Lizorkin and Besov spaces has been very well developed in the past decades, the multi-parameter counterpart of such a theory is still absent. The main purpose of this paper is to develop a theory of multi-parameter Triebel-Lizorkin and Besov spaces using the discrete Littlewood-Paley-Stein analysis in the setting of implicit multi-parameter structure. It is motivated by the recent work of Han and Lu in which they established a satisfactory theory of multi-parameter Littlewood-Paley-Stein analysis and Hardy spaces associated with the flag singular integral operators studied by Muller-Ricci-Stein and Nagel-Ricci-Stein. We also prove the boundedness of flag singular integral operators on Triebel-Lizorkin space and Besov space. Our methods here can be applied to develop easily the theory of multi-parameter Triebel-Lizorkin and Besov spaces in the pure product setting.
