IntroductionThis paper explored the impact of COVID-19 transmission rate on co-movement of China’s stock markets.MethodsBy employing the rolling time series model to measure the COVID-19 transmission rate and DCC-GARCH model to analyze co-movement of China’s Stock markets, this paper managed to demonstrate a significant correlation between COVID-19 transmission rate and co-movement of China’s stock markets.ResultsThe findings revealed that co-movement of China’s stock markets was significantly affected by the COVID-19 transmission rate during the pandemic period. As the transmission rate accelerated, the co-movement among China’s stock markets intensified, indicating that the shock of the pandemic strengthened their interconnectedness, leading to a broader spread of risk.DiscussionThis result suggests that the pandemic shock not only impacted individual stock markets but also intensified the correlations and risk spillovers among them. Such findings have important implications for investors, policymakers, and regulators. Therefore, during the virus outbreak stage, attempting to diversify risk by investing funds into different stock markets is ineffective; a more viable strategy to minimize losses would be to sell their held stocks. For policymakers, promptly introducing and effectively implementing virus prevention and containment measures is a feasible approach to mitigate the epidemic’s impact on domestic financial markets and stabilize their development.
We prove two homotopy decomposition theorems for the loops on simply-connected co- H H -spaces, including a generalization of the Hilton-Milnor Theorem. Several examples are given.
AbstractWe consider the set (of homotopy classes) of co-H-structures on a Moore space M(G,n), where G is an abelian group and n is an integer ≥ 2. It is shown that for n > 2 the set has one element and for n = 2 the set is in one-one correspondence with Ext(G, G ⊗ G). We make a detailed investigation of the co-H-structures on M(G, 2) in the case G = ℤm, the integers mod m. We give a specific indexing of the co-H-structures on M(ℤm, 2) and of the homotopy classes of maps from M(ℤm, 2) to M(ℤn, 2) by means of certain standard homotopy elements. In terms of this indexing we completely determine the co-H-maps from M{ℤm, 2) to M(ℤn, 2) for each co-H-structure on M(ℤm, 2) and on M(ℤn, 2). This enables us to describe the action of the group of homotopy equivalences of M(ℤn, 2) on the set of co-H-structures of M(ℤm, 2). We prove that the action is transitive. From this it follows that if m is odd, all co-H-structures on M(ℤm, 2) are associative and commutative, and if m is even, all co-H-structures on M(ℤm, 2) are associative and non-commutative.
In [2], chapter S, and also in the ATLAS ([1], p. 131), we give two presentations for 3 · Suz: 2, the normalizer of a certain 3-element in Conway's largest sporadic simple group Co1. These presentations extend naturally to presentations for groups having Co1 × 2 as image, leading to conjectured presentations for Co1 × 2 and Co1 (see [1], p. 183, although the form of one of the presentations there is slightly different from what we give here).