scholarly journals Quantum moment map and obstructions to the existence of closed Fedosov star products

2021 ◽  
Vol 163 ◽  
pp. 104118
Author(s):  
Akito Futaki ◽  
Laurent La Fuente-Gravy
Keyword(s):  
2002 ◽  
Vol 14 (06) ◽  
pp. 601-621 ◽  
Author(s):  
KENTARO HAMACHI

We study a quantum moment map and propose an invariant for G-invariant star products on a G-transitive symplectic manifold. We start by describing a new method to construct a quantum moment map for G-invariant star products of Fedosov type. We use it to obtain an invariant that is invariant under G-equivalence. In the last section we give two simple examples of such invariants, which involve non-classical terms and provide new insights into the classification of G-invariant star products.


2021 ◽  
Vol 384 (1) ◽  
pp. 245-277
Author(s):  
Mykola Dedushenko
Keyword(s):  

2020 ◽  
Vol 66 (9) ◽  
pp. 3879-3902 ◽  
Author(s):  
Ruomeng Cui ◽  
Meng Li ◽  
Qiang Li

Consumers regard product delivery as an important service component that influences their shopping decisions on online retail platforms. Delivering products to customers in a timely and reliable manner enhances customer experience and companies’ profitability. In this research, we explore the extent to which customers value a high-quality delivery experience when shopping online. Our identification strategy exploits a natural experiment: a clash between SF Express and Alibaba, the largest private logistics service provider with the highest reputation in delivery quality in China and the largest online retail platform in China, respectively. The clash resulted in Alibaba unexpectedly removing SF Express as a shipping option from Alibaba’s retail platform for 42 hours in June 2017. Using a difference-in-differences design, we analyze the market performance of 129,448 representative stock-keeping units on Alibaba to quantify the economic value of a high-quality delivery service to sales, product variety, and logistics rating. We find that the removal of the high-quality delivery option from Alibaba’s retail platform reduced sales by 14.56% during the clash, increased the contribution of long-tail to total sales—sales dispersion—by 3%, but did not impact the variety and logistics rating of sold products. Furthermore, we also identify product characteristics that attenuate the value of high-quality logistics and find that the removal of SF Express is more obstructive for (1) star products as compared with long-tail products because the same star products are likely to be supplied by competing retail platforms that customers can easily switch to, (2) expensive products because customers need a reliable delivery service to protect their valuable items from damage or loss, and (3) less-discounted products because customers are more willing to sacrifice the service quality over a price markdown. This paper was accepted by Victor Martínez-de-Albéniz, operations management.


2014 ◽  
Vol 66 (4) ◽  
pp. 563-581
Author(s):  
Takashi Hashimoto
Keyword(s):  

1996 ◽  
Vol 126 (1) ◽  
pp. 65-84 ◽  
Author(s):  
Peter Heinzner ◽  
Alan Huckleberry

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