Given two Banach spaces E, F, let B（E, F） be the set of all bounded linear operators from E into F, ∑r the set of all operators of finite rank r in B（E, F）, and ∑r^# the number of path connected components of ∑...Given two Banach spaces E, F, let B（E, F） be the set of all bounded linear operators from E into F, ∑r the set of all operators of finite rank r in B（E, F）, and ∑r^# the number of path connected components of ∑r. It is known that ∑r is a smooth Banach submanifold in B（E,F） with given expression of its tangent space at each A ∈ ∑r. In this paper, the equality ∑r^# = 1 is proved. Consequently, the following theorem is obtained： for any nonnegative integer r,∑r is a smooth and path connected Banach submanifold in B（E, F） with the tangent space TA∑r = {B E B（E,F） ： BN（A） belong to R（A）} at each A ∈ ∑r if dim F = ∞. Note that the routine method can hardly be applied here. So in addition to the nice topological and geometric property of ∑r the method presented in this paper is also interesting. As an application of this result, it is proved that if E = R^n and F = R^m, then ∑r is a smooth and path connected submanifold of B（R^n,R^m） and its dimension is dim ∑r = （m ＋ n）r- r^2 for each r, 0≤r 〈 min{n,m}.展开更多
Based on the problems found in the study of historical blocks, the paper puts forward the quantifiable standards for maintaining the spatial characteristics of historical blocks by analyzing the key factors of update ...Based on the problems found in the study of historical blocks, the paper puts forward the quantifiable standards for maintaining the spatial characteristics of historical blocks by analyzing the key factors of update strategy that influence the spatial characteristics of historical blocks. Combined with the update planning of the north section of Chuancheng Street, a historic block in Handan City, the block space is digitally simulated by space syntax software Depthmap, to study the behavior path and visual field in the renewal of historic blocks. The development strategy of both protection and renewal is put forward, in order to accumulate experience for the sustainable development of historic blocks.展开更多
The authors give the condition that the Bergman kernel function on the first type of Cartan-Hartogs domain exists zeros.If the Bergman kernel function of this type of domain has zeros,the zero set is composed of sever...The authors give the condition that the Bergman kernel function on the first type of Cartan-Hartogs domain exists zeros.If the Bergman kernel function of this type of domain has zeros,the zero set is composed of several path-connected branches,and there exists a continuous curve to connect any two points in the non-zero set.展开更多
基金Supported by the National Science Foundation of China (Grant No.10671049 and 10771101).
文摘Given two Banach spaces E, F, let B（E, F） be the set of all bounded linear operators from E into F, ∑r the set of all operators of finite rank r in B（E, F）, and ∑r^# the number of path connected components of ∑r. It is known that ∑r is a smooth Banach submanifold in B（E,F） with given expression of its tangent space at each A ∈ ∑r. In this paper, the equality ∑r^# = 1 is proved. Consequently, the following theorem is obtained： for any nonnegative integer r,∑r is a smooth and path connected Banach submanifold in B（E, F） with the tangent space TA∑r = {B E B（E,F） ： BN（A） belong to R（A）} at each A ∈ ∑r if dim F = ∞. Note that the routine method can hardly be applied here. So in addition to the nice topological and geometric property of ∑r the method presented in this paper is also interesting. As an application of this result, it is proved that if E = R^n and F = R^m, then ∑r is a smooth and path connected submanifold of B（R^n,R^m） and its dimension is dim ∑r = （m ＋ n）r- r^2 for each r, 0≤r 〈 min{n,m}.
基金Sponsored by Graduate Demonstration Course Construction Project of Hebei Province(KCJSX2020081)。
文摘Based on the problems found in the study of historical blocks, the paper puts forward the quantifiable standards for maintaining the spatial characteristics of historical blocks by analyzing the key factors of update strategy that influence the spatial characteristics of historical blocks. Combined with the update planning of the north section of Chuancheng Street, a historic block in Handan City, the block space is digitally simulated by space syntax software Depthmap, to study the behavior path and visual field in the renewal of historic blocks. The development strategy of both protection and renewal is put forward, in order to accumulate experience for the sustainable development of historic blocks.
基金supported by the National Natural Science Foundation of China(No.11871044)the Natural Science Foundation of Hebei Province(No.A2019106037)
文摘The authors give the condition that the Bergman kernel function on the first type of Cartan-Hartogs domain exists zeros.If the Bergman kernel function of this type of domain has zeros,the zero set is composed of several path-connected branches,and there exists a continuous curve to connect any two points in the non-zero set.
