Modeling of Covid‐19 trade measures on essential products: a multiproduct, multicountry spatial price equilibrium framework

Abstract

In this paper, we develop a unified variational inequality framework in the context of spatial price network equilibrium problems that handles multiple products with multiple demand and supply markets in multiple countries as well as multiple transportation routes. The model incorporates a plethora of distinct trade measures, which is particularly important in the pandemic, as PPEs and other essential products are in high demand, but short in supply globally. In the model, product flows as well as prices at the supply markets and the demand markets in different countries are variables that allows us to seamlessly introduce various trade measures, including tariffs, quotas, as well as price floors and ceilings. Qualitative properties are analyzed. Numerical examples are provided to illustrate the impacts of the trade measures on equilibrium product path and link flows, and on prices, and demand and supply quantities. Given the relevance of the trade measures in the world today and discussions concerning the impacts, the framework constructed in this paper is especially timely.

Food security and multicommodity agricultural international trade: Quantifying optimal consumer subsidies for nutritional needs

“…The spatial price equilibrium framework, in a variational inequality context (cf. Florian and Los, 1982; Dafermos and Nagurney, 1984), has yielded rich modeling advances and applications, especially to agricultural products (see, e.g.,Nagurney and Aronson, 1989; Nagurney, Li, and Nagurney, 2014; Nagurney et al., 2022; Nagurney and Besik, 2022; Nagurney et al., 2023). Definition A multicommodity shipment and Lagrange multiplier pattern $$(Q^*,\lambda ^*)\in {\cal K}^1$$ is an international trade equilibrium with food security nutritional minimum standards if it satisfies the following conditions: for each commodity h ; $$h=1,\ldots ,H$$, and for each pair of country supply and demand markets $$(i,j)$$; $$i=1,\ldots ,n$$; $$j=1,\ldots ,n$$: …”

“…The research in this paper builds on the work on spatial price equilibrium modeling (see Samuelson, 1952; Takayama and Judge, 1964, 1971) but utilizes the theory of variational inequalities (cf. Florian and Los, 1982; Dafermos and Nagurney, 1984; Nagurney and Aronson, 1989; Nagurney, 1999), with specific note on policies (Nagurney, Thore, and Pan, 1996; Nagurney, Nicholson, and Bishop, 1996; Nagurney et al., 2014, 2019, 2022, 2023). Spatial price equilibrium models have had wide applications to agricultural commodities and, therefore, this foundational framework is a reasonable one in which to also incorporate minimum nutritional standards for consumers in different countries.…”

Nonlinear time‐series forecasts for decision support: short‐term demand for ICU beds in Santiago, Chile, during the 2021 COVID‐19 pandemic

“…The global healthcare disaster caused by the COVID‐19 pandemic has endangered and disrupted the lives of billions around the world, resulting in illnesses and deaths (Nagurney et al., 2021 ). By late July 2020, with declining rates of new cases, Chile had achieved a partial control of the growth rates of COVID‐19.…”