# COVID-19's Impact on International Trade
## 3 Results  
### World Countries on the PageRank-CheiRank Plane  
The top 20 countries according to the PageRank, CheiRank, ImportRank and ExportRank are given in Figure 1 for the years 2018, 2019 and 2020. For each ranking, the top three countries are unchanged for the three consecutive years. The top three countries are either the USA, China and Germany for import-related rankings--i.e., ImportRank and PageRank--or China, the USA and Germany for export-related rankings--i.e., ExportRank and CheiRank. Globally, along this time period, the ImportRank and the ExportRank are quite stable for the top 20 main international trade players, suggesting that their relative total trade capacities were not significantly affected by COVID-19. Indeed, from 2018 to 2020, we observe 10 countries for which the rank did not change, while the rank of the others changed by at most \(\pm 2\) positions. However, there are the following exceptions: Russia, which significantly worsened in terms of both its ImportRank (\(\hat{K}=19\to 23\)) and ExportRank (\(\hat{K}^{*}=9\to 20\)); the United Arab Emirates (UAE), which worsened in terms of its ImportRank (\(\hat{K}=18\to 29\)--the UAE does not even appear in the top 20 exporters) and Vietnam, which improved its ExportRank (\(\hat{K}^{*}=20\to 15\)). The relative loss of export volume for Russia and the UAE can be attributed to the significant global reduction of world production and also of air traffic induced by the COVID-19 lockdown. This automatically reduced the global requests for mineral fuels (petrol, gas...) which dominate the trade flows of Russia and the UAE. In contrast, the Vietnamese economy was one of the most resilient during the COVID-19 crisis [44]. In contrast to the import-export description, based only on the relative amount of total export and import volumes, the PageRank and CheiRank description takes account of the structure of the WTN and consequently allows us to rank countries according to their relative efficiency to import and export commodities. Roughly speaking, countries importing from (exporting to) a large variety of countries will obtain a better PageRank (CheiRank) than ImportRank (ExportRank); e.g., India, in 2018, which has the 16 th export volume (10 th import volume), occupies the \(K^{*}=7\) (\(K=6\)) position in the CheiRank (PageRank), suggesting a more important role in the WTN structure than would be inferred by focusing only on the import-export point of view. For 2018, we can observe similar cases for the UAE (\(\hat{K}=18\to K=9\), \(\hat{K}^{*}=21\to K^{*}=10\)) and for Russia (\(\hat{K}^{*}=9\to K^{*}=4\)). Taking the example of Russia, the diversity of its trade relations for mineral fuels, involving both European and Asian countries, is much better captured by the PageRank-CheiRank picture, which takes account of the complexity of the WTN and the multiplicity of cascades of commercial links. Conversely, despite the fact that Japan's import and export volumes were the fourth most important in 2018, Japan's position dropped to \(K=10\) in PageRank and \(K^{*}=8\) in CheiRank, suggesting that the centrality of Japan in the WTN is weaker than expected, certainly due to a lack of diversity of commercial partners. The PageRank-CheiRank picture allows us to detect a rewiring of the WTN due to the COVID-19 pandemic. Indeed, from Figure 1 (two first columns), we observe more abrupt variations from 2019 to 2020 (up to \(+6\) and \(-20\) positions for the PageRank of Turkey and UAE, respectively; up to \(+7\) and \(-22\) positions for the CheiRank of Brazil and UAE, respectively) than from 2018 to 2019 (up to \(+3\) and \(-3\) positions for the PageRank of Russia and Belgium, respectively; up to \(+2\) and \(-2\) positions for the CheiRank of, e.g., Spain and Brazil, respectively). Mimicking the loss of import and export volumes experienced by Russia and the UAE from 2018 to 2020, Russia's CheiRank (PageRank)drops by 11 (7) positions and the UAE's CheiRank (PageRank) drops by 22 (20) positions.