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A. I. Kozhanov 《Siberian Mathematical Journal》2005,46(5):841-856
We study the inverse problem of finding the coefficient of thermal conductivity of the heat equation (along with the solution). As the overdetermination condition we take the values of the solution at the final time. Existence of a regular solution is proven. 相似文献
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A biclique of a graph G is a maximal induced complete bipartite subgraph of G. The biclique graph of G, denoted by , is the intersection graph of the bicliques of G. We say that a graph G diverges (or converges or is periodic) under an operator F whenever ( for some m, or for some k and , respectively). Given a graph G, the iterated biclique graph of G, denoted by , is the graph obtained by applying the biclique operator k successive times to G. In this article, we study the iterated biclique graph of G. In particular, we classify the different behaviors of when the number of iterations k grows to infinity. That is, we prove that a graph either diverges or converges under the biclique operator. We give a forbidden structure characterization of convergent graphs, which yield a polynomial time algorithm to decide if a given graph diverges or converges. This is in sharp contrast with the situsation for the better known clique operator, where it is not even known if the corresponding problem is decidable. © 2012 Wiley Periodicals, Inc. J. Graph Theory 73: 181–190, 2013 相似文献
25.
Magnus Pfaffenbach Ian Bakanas Nicholas R. O'Connor Jessica L. Herrick Richmond Sarpong 《Angewandte Chemie (International ed. in English)》2019,58(43):15304-15308
Divergent and enantiospecific total syntheses of the indolosesquiterpenoids xiamycins A, C, F, H and oridamycin A have been accomplished. The syntheses, which commence from (R)‐carvone, employ a key photoinduced benzannulation sequence to forge the carbazole moiety characteristic of these natural products. Late‐stage diversification from a common intermediate enabled the first syntheses of xiamycins C and F, and an unexpected one‐pot oxidative decarboxylation, which may prove general, led to xiamycin H. All synthetic intermediates and the natural products were tested for anti‐fungal activity. Xiamycin H emerged as an inhibitor of three agriculturally relevant fungal pathogens. 相似文献
26.
Divergent Total Syntheses of Enmein‐Type Natural Products: (−)‐Enmein, (−)‐Isodocarpin,and (−)‐Sculponin R
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Saiyong Pan Sicong Chen Guangbin Dong 《Angewandte Chemie (International ed. in English)》2018,57(21):6333-6336
Divergent total syntheses of the enmein‐type natural products (?)‐enmein, (?)‐isodocarpin, and (?)‐sculponin R have been achieved in a concise fashion. Key features of the strategy include 1) an efficient early‐stage cage formation to control succeeding diastereoselectivity, 2) a one‐pot acylation/akylation/lactonization to construct the C‐ring and C8 quarternary center, 3) a reductive alkenylation approach to construct the enmain D/E rings and 4) a flexible route to allow divergent syntheses of three natural products. 相似文献
27.
Huaping Xu Xiaoyu Kong Mengjie Cen Prof. Dr. Ze-Feng Xu Prof. Dr. Shengguo Duan Prof. Dr. Chuan-Ying Li 《European journal of organic chemistry》2023,26(8):e202201417
Cyclopropane, dihydropyrrole, and azepane ring systems were synthesized conveniently from sulfinate-tethered triazoles. The divergent synthetic strategy started with the unique 1,3-sulfinate migration of an α-imino carbene. The efficient reaction allowed control of the zwitterion bearing multiple reactive sites depending on the increased stability of the resulting carbocation and anion. The sulfinate was converted to a sulfone after the group migration, and a stable anion bearing two electron-withdrawing groups was thus formed. Catalytic amounts of iodide acted as a switch for the synthesis of cyclopropanes and dihydropyrroles. The reaction merits including readily available substrates, mild reaction conditions, and excellent functional group compatibility qualified this protocol a possible synthetic tool for cyclic compounds, especially for N-heterocycles. 相似文献
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Markus Brede 《The Ramanujan Journal》2009,19(3):305-324
Let f be an analytic function in a complex domain D and (without loss of generality) assume 0∈D. Then the paper’s aim is to derive a Taylor-like integral expression for f, i.e. an integral representation analogous to the corresponding power series, say, ∑
k=0∞
a
k
t
k
/k!.
We start from the simplest case f(t)=e
t
, which leads to the identity
valid for Re
t>0, Γ denoting the Euler gamma function. This statement turns out as the result of a summation of the divergent integral ∫
−∞∞
t
y
/Γ(y+1)dy, so that, in the sense of summability, the formula
holds, i.e. a perfect integral analogue of the corresponding series.
Next, we consider the important case of polynomial, resp. monomial f. Then we will apply our statements (on polynomials) to the general case of any function f analytic at 0. Particularly, we will deduce some remarkable statements about the function log (1+x) and its powers, i.e. on the Stirling numbers of the first kind and their generalization to C, the so-called Butzer-Stirling functions. Finally we present a general method for deriving results for large classes of other
functions.
Dedicated to Prof. Dr. Paul L. Butzer, Aachen. 相似文献
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