Frontiers of Mathematics in China

ISSN 1673-3452

ISSN 1673-3576(Online)

CN 11-5739/O1

Postal Subscription Code 80-964

2018 Impact Factor: 0.565

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, Volume 17 Issue 3

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SURVEY ARTICLE
Applications of multiresolution analysis in Besov-Q type spaces and Triebel-Lizorkin-Q type spaces
Pengtao LI, Wenchang SUN
Front. Math. China. 2022, 17 (3): 373-435.  
https://doi.org/10.1007/s11464-022-1015-0

Abstract   PDF (514KB)

In this survey, we give a neat summary of the applications of the multi-resolution analysis to the studies of Besov-Q type spaces B ˙ p,q γ1,γ2(n) and Triebel-Lizorkin-Q type spaces B˙p, qγ1, γ2( n). We will state briefly the recent progress on the wavelet characterizations, the boundedness of Calderón-Zygmund operators, the boundary value problem of B ˙ p,q γ1,γ2(n) and F ˙ p,q γ1,γ2(n). We also present the recent developments on the well-posedness of fluid equations with small data in B˙p, qγ1, γ2( n) and F ˙p ,qγ1,γ2( n).

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Computation of the cohomology rings of Kac-Moody groups, their flag manifolds and classifying spaces
Xu-an ZHAO
Front. Math. China. 2022, 17 (3): 437-454.  
https://doi.org/10.1007/s11464-022-1016-z

Abstract   PDF (232KB)

In this paper we introduce the history and present situation of the computation of the cohomology rings of Kac-Moody groups, their flag manifolds and classifying spaces, and give some problems and conjectures that deserve further study.

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RESEARCH ARTICLE
Boundary behavior of harmonic functions on metric measure spaces with non-negative Ricci curvature
Wanwan YANG, Bo LI
Front. Math. China. 2022, 17 (3): 455-471.  
https://doi.org/10.1007/s11464-022-1017-y

Abstract   PDF (922KB)

Let (X, d, μ) be a metric measure space with non-negative Ricci curvature. This paper is concerned with the boundary behavior of harmonic function on the (open) upper half-space X×+. We derive that a function f of bounded mean oscillation (BMO) is the trace of harmonic function u(x,t ) on X×+,u(x,0 )=f( x), whenever u satisfies the following Carleson measure condition

supxB,rB 0rBfB(x B, rB)|t u(x ,t)|2d μ (x)dttC<

where =( x ,t) denotes the total gradient and B(xB,r B) denotes the (open) ball centered at xB with radius rB. Conversely, the above condition characterizes all the harmonic functions whose traces are in BMO space.

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Injective coloring of planar graphs with girth 5
Yuehua BU, Piaopiao YE
Front. Math. China. 2022, 17 (3): 473-484.  
https://doi.org/10.1007/s11464-022-1018-x

Abstract   PDF (233KB)

A coloring of a graph G is injective if its restriction to the neighbour of any vertex is injective. The injective chromatic number Xi(G) of a graph G is the leastk such that there is an injective k-coloring. In this paper, we prove that for each planar graph with g5 and Δ(G)20, χi(G)Δ(G)+3.

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The cosemisimplicity and cobraided structures of monoidal comonads
Xiaohui ZHANG, Hui WU
Front. Math. China. 2022, 17 (3): 485-499.  
https://doi.org/10.1007/s11464-022-1019-9

Abstract   PDF (234KB)

In this paper, we study the category of corepresentations of a monoidal comonad. We show that it is a semisimple category if and only if the monoidal comonad is a cosemisipmle (coseparable) comonad, and it is a braided category if and only if the monoidal comonad admit a cobraided structure. At last, as an application, the braided structure and the semisimplicity of the Hom-comodule category of a monoidal Hom-bialgebra are discussed.

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5 articles