Quiver Grassmannians associated with string modules

We provide a technique to compute the Euler characteristic of a class of projective varieties called quiver Grassmannians. This technique applies to quiver Grassmannians associated with "orientable string modules". As an application we explicitly compute the Euler characteristic of quiver Grassmannians associated with indecomposable preprojective, preinjective and regular homogeneous representations of an affine quiver of type $\tilde{A}_{p,1}$. For $p=1$, this approach provides another proof of a result due to P. Caldero and A. Zelevinsky in \cite{CZ}.Comment: Minor changes. Accepted at the Journal Of Algebraic Combinatoric

Geometry of quiver Grassmannians of Dynkin type with applications to cluster algebras

The paper includes a new proof of the fact that quiver Grassmannians associated with rigid representations of Dynkin quivers do not have cohomology in odd degrees. Moreover, it is shown that they do not have torsion in homology. A new proof of the Caldero-Chapoton formula is provided. As a consequence a new proof of the positivity of cluster monomials in the acyclic clusters associated with Dynkin quivers is obtained. The methods used here are based on joint works with Markus Reineke and Evgeny Feigin

Are R&D subsidies provided optimally? Evidence from a simulated agency-firm stochastic dynamic game

By means of a simulated funding-agency/supported-firm stochastic dynamic game, this paper firstly shows that not only the level of R&D performed by firms is underprovided (as maintained by traditional literature on the subject), but also the level of the subsidy provided by the funding (public) agency (used to correct exactly for the corporate R&D shortage). This event is due to externalities generated by the agency-firm strategic relationship. Two versions of the model are simulated and compared: one assuming rival behaviors between companies and agency, and one associated to the Social-planner (or cooperative) strategy. Secondly, the paper looks at what “welfare” implications are associated to different degree of funding effect’s persistency. Three main conclusions are drawn: (i) the relative quota of subsidy to R&D is undersized in the rival compared to the Social-planner model; (2) the rivalry strategy generates distortions that favor the agency compared to firms; (3) when passing from less persistent to more persistent R&D additionality/crowding-out effect, the lower the bias the greater the variance is and vice versa. As for the management of R&D funding policies, all the elements favouring greater collaboration between agency and firm objectives can help current R&D support to reach its social optimum.R&D subsidies, Rivalry vs. cooperation, Dynamic-stochastic games, Simulations

The redistributive role of non-profit organizations

By starting from the consideration that non-profit organizations cover a significant re-distributive function beside that of governmental agencies, the paper questions why government prefers to finance via transfers private entities likewise lucrative and non-lucrative entities rather than produce these goods directly. By generalizing the Hansmann (1996) theory, we propose a “make or buy” approach in which the choice among three different ownership regimes (governmental, non-profit and for-profit) providing services in public benefit oriented sectors is affected not only by costs reduction (X-efficiency) but also by the level of transfers (degree of “redistribution”) decided at a political level.non-profit organizations; redistribution; property rights

Evaluating the Effect of Public Subsidies on firm R&D activity: an Application to Italy Using the Community Innovation Survey

WP 09/2008; The aim of the paper is twofold: to verify a full policy failure of public support on private R&D effort, when in presence of a potential plurality of public incentives; to compare the most recent econometric methods used for the analysis of the input additionality. Compared to previous studies our work wants to trace out an advance in two directions: adding more robustness by comparing results from various econometric techniques and providing an analysis of the R&D policy effect behind the average results. A by-product of the paper is a taxonomy of the econometric methods used in the literature, according to the structure of the models, the type of dataset and the available policy information. We exploit the third wave of the Community Innovation Survey for Italy (1998-2000) with a sample size of 1,221 supported and 1,319 non-supported firms. Given the used type of data, the article presents two main limits: first, we do not know the level of the subsidy, so that we can control only for the presence of a total crowding-out; second, we can check only the short-run effect of the supporting policy, while an increase in the private R&D effort could be more likely in the medium term. Our results suggest that: 1. the main factors influencing the probability to participate to the incentive policy are R&D experience, human skills, liquidity constraints, but also foreign capital ownership; 2. on average, the total substitution of private funding by the public one is excluded for Italy as a whole, although some cases of total crowding-out are found: low knowledge intensive services, very small firms (10-19 employees) and the auto-vehicle industry. We get, on average, 885 additional thousand Euros of R&D expenditure per firm with a ratio equal to 4.62: it means that if a generic control unit does 1 thousand Euros of R&D expenditure a matched treated does 4.62 thousand Euros. The additionality for the R&D intensity is about 0.014 with a ratio of about 2.67

Degenerate flag varieties of type A and C are Schubert varieties

We show that in type A or C any degenerate flag variety is in fact isomorphic to a Schubert variety in an appropriate partial flag manifold.Comment: The new version includes an appendix where we discuss desingularizations. 14 page

Geometry of quiver Grassmannians of Kronecker type and canonical basis of cluster algebras

We study quiver Grassmannians associated with indecomposable representations of the Kronecker quiver. We find a cellular decomposition of them and we compute their Betti numbers. As an application, we give a geometric realization of the "canonical basis" of cluster algebras of Kronecker type (found by Sherman and Zelevinsky) and of type $A_2^{(1)}$.Comment: 21 page

Measuring Intersectoral Knowledge Spillovers: an Application of Sensitivity Analysis to Italy

R&D spillovers are unanimously considered as one of the main driving forces of technical change, innovation and economic growth. This paper aims at measuring inter-industrial R&D spillovers, as a useful information for policy-makers. We apply an “uncertainty-sensitivity analysis” to the Italian input-output table of intermediate goods split into 31 economic sectors for the year 2000. The value added of using this methodology is the opportunity of distinguishing (separately) between spillover effects induced by productive linkages (the Leontiev forward multipliers) and those activated by R&D investments, capturing also the uncertain and non-linear nature of the relations between spillovers and factors affecting them.R&D spillovers, Input-output models, Sensitivity analysis, Monte Carlo simulations

Evaluating the Effect of Public Subsidies on firm R&D activity: an Application to Italy Using the Community Innovation Survey

The aim of the paper is twofold: to verify a full policy failure of public support on private R&D effort, when in presence of a potential plurality of public incentives; to compare the most recent econometric methods used for the analysis of the input additionality. Compared to previous studies our work wants to trace out an advance in two directions: adding more robustness by comparing results from various econometric techniques and providing an analysis of the R&D policy effect behind the average results. A by-product of the paper is a taxonomy of the econometric methods used in the literature, according to the structure of the models, the type of dataset and the available policy information. We exploit the third wave of the Community Innovation Survey for Italy (1998-2000) with a sample size of 1,221 supported and 1,319 non-supported firms. Given the used type of data, the article presents two main limits: first, we do not know the level of the subsidy, so that we can control only for the presence of a total crowding-out; second, we can check only the short-run effect of the supporting policy, while an increase in the private R&D effort could be more likely in the medium term. Our results suggest that: 1. the main factors influencing the probability to participate to the incentive policy are R&D experience, human skills, liquidity constraints, but also foreign capital ownership; 2. on average, the total substitution of private funding by the public one is excluded for Italy as a whole, although some cases of total crowding-out are found: low knowledge intensive services, very small firms (10-19 employees) and the auto-vehicle industry. We get, on average, 885 additional thousand Euros of R&D expenditure per firm with a ratio equal to 4.62: it means that if a generic control unit does 1 thousand Euros of R&D expenditure a matched treated does 4.62 thousand Euros. The additionality for the R&D intensity is about 0.014 with a ratio of about 2.67.Business R&D; Public Incentives; Econometric Evaluation