Benedetto Manca (University of Cagliari) 

will give a presentation on : 

Random Projections for Mathematical Programming. 

Abstract : 

Random projections are random linear maps which approximately preserve geometrical quantities. The Johson-Lindenstrauss Lemma states that there exist random projections with a relatively small number of rows which preserve the pairwise Euclidean distances among a set of points. 
In the past years several results on the application of random projections to Mathematical Programming instances are being obtained, showing that it is possible to obtain an approximate formulation with less decision variables and constraints and therefore easier to solve. 
In this talk I will introduce the generic framework of random projections for Mathematical Programming formulations and I will present more in details some results in the case of Linear Programming, Quadratic Programming and the Minimum Sum of Squares problem. 

Yukihiro Nishimura (Osaka University) 

will give a presentation on : 

Tax Reform on Monopoly Platformer in Borderless Economy: The Incidence on Prices and Efficiency Consequences. 

Abstract : 

As development of online market brings ongoing concerns that foreign app suppliers avoid value-added tax (VAT) in a domestic country, some countries design a tax reform which makes platform pay VAT instead of app suppliers (platform taxation). In the market where the monopoly platformer determines the prices of the network good and the commission fee of the platform services (with online apps as a representative example), this study investigates whether the prevention of tax leaks by platform tax improves the welfare of the host country, as well as the extent of the cross-market incidence of the two-sided market. We find that the tax reform reduces foreign app suppliers and consumption of a network good such as smartphones, with substantial extent of cross-market pass-through. The effect of the tax reform on home app suppliers crucially depends on the responsiveness of the app supplies from the number of users, which we call entry elasticity. Platform tax also increases the tax burden laid on the network product, but the monopoly seller let the increase of the tax burden born entirely by consumers. We also show that digitalization reduces the loss of welfare as well as tax planning by the platformer.