On the 3-form formulation of axion potentials from D-brane instantons

The study of axion models and quantum corrections to their potential has experienced great progress by phrasing the axion potential in terms of a 3-form field eating up the 2-form field dual to the axion. Such reformulation of the axion potential has been described for axion monodromy models, and for axion potentials from non-perturbative gauge dynamics. In this paper we propose a 3-form description of the axion potentials from non-gauge D-brane instantons. Interestingly, the required 3-form field does not arise in the underlying geometry, but rather shows up in the KK compactification in the generalized geometry obtained when the backreaction of the D-brane instanton is taken into account.Comment: 17 pages. Minor change

Backreacting D-brane instantons on branes at singularities

Non-perturbative D-brane instanton effects in 4d N = 1 string compactifications can be geometrized in terms of a backreacted generalized geometry. We extend earlier results to setups in which the D-brane instanton is charged under the 4d gauge symmetries, and show that the backreacted topology yields the correct charged field theory operators in the 4d effective action. In type IIA models with D6-branes, the backreaction of D2-brane instantons forces the recombination of D6-branes, such that the 4d charged field theory operators arise from basic worldsheet instantons in the backreacted geometry. We provide large classes of examples of D2-brane instanton effects on intersecting D6-brane systems in local models mirror to D3-branes at singularities. The backreacted geometry and the field theory operators are easily encoded in terms of simple operation in the graphs arising from the underlying dimer diagrams. This description agrees, in the appropriate cases, with the complex deformations triggered by certain fractional branes at the bottom of duality cascades.Comment: 40 pages, 27 Figures,v2 Minor correction

Welfare, Revenue and Indirect Tax Harmonization under the Origin Principle

This paper discusses whether some propositions concerning the effects of indirect tax harmonization that have been derived when taxes are levied on a destination basis and revenue is returned to the individuals as a lump-sum transfer can, when accurately reformulated, be extended to a framework where commodities are taxed according to the origin principle and the governments use their revenue to finance the purchase of goods and services. Using a two-country model, it is argued that a non-uniform proportional convergence of domestic taxes towards a properly designed «average » tax structure can be characterized as potentially Pareto-improving. However, these reforms will not, in general, lead to a strict Pareto-improvement where every country is better off without any need for international transfers.: indirect tax harmonization, origin principle, reform of commodity taxes.

Immigration policy with partisan parties

This paper analyzes the political economy of immigration when the salient electoral issue is the level of immigrants and the relevant immigration policy is the expenditure in immigration control. We consider that immigration affects voters’ welfare through economic and non economic factors. We model political competition `a la Wittman with the ideology of parties endogenously determined at equilibrium. At equilibrium, parties propose different levels of immigration, located to the left and to the right of the median voter’s ideal point, and combine skilled and unskilled workers among their constituencies. Numerical simulations provide the levels of immigration proposed by the two parties and the composition of parties’ constituencies as we vary the efficacy of immigration control and the intensity of immigration aversion.Immigration, ideological parties, unskilled and skilled labor

Inflation risks and inflation risk premia

This paper investigates the link between the perceived inflation risks in macroeconomic forecasts and the inflation risk premia embodied in financial instruments. We first provide some stylized facts about the term structure of inflation compensation, inflation expectations and inflation risk premia in the euro area bond market. Latent factor models like ours fit data well, but are often critisized for lacking economic interpretation. Using survey inflation risks, we show that perceived asymmetries in inflation risks help interpret the dynamics of long-term inflation risk premia, even after controlling for a large number of macro and financial factors. JEL Classification: G12, E31, E43Affine term structure models, inflation compensation, inflation risk, inflation risk premia, inflation risks, state-space modelling

What drives euro area break-even inflation rates?

The yield spread between nominal and inflation-linked bonds (or break-even inflation rates, BEIR) is a fundamental indicator of inflation expectations (and associated premia). This paper investigates which macroeconomic and financial variables explain BEIRs. We evaluate a large number of potential explanatory variables through Bayesian model selection techniques and document their explanatory power at different horizons. At short horizons, actual inflation dynamics is the main determinant of BEIRs. At long horizons, financial variables (i.e. term spread, bond market volatility) become increasingly relevant, but confidence and cyclical indicators remain important. JEL Classification: C11, C52, E31Bayesian model selection, break-even inflation rates, business cycle indicators, inflation risk premia

The spatial effect of intra-metropolitan agglomeration economies

This study deals with the role of spatial accessibility to agglomeration economies in the change in spatial structure of industrial employment for the case of the Barcelona Metropolitan Region of Barcelona (BMR). Using the growth in gross density of municipal employment between 1986 and 1996 for seven manufacturing industries as an indicator of changes in the spatial structure of employment, an exploration is made of the spatial impact of agglomeration economies operating on a local scale – the municipality and three areas 5, 8 and 12 kilometres away surrounding the municipality itself - , agglomeration economies emerging from CBD and the main specialised subcentres in the region, and the network economies associated with the total jobs in the region, access to which depends on the distance from the main transport infrastructuresAgglomeration economies, industrial employment growth, intra-metropolitan localisation, spatial structure.

Reporting biases and survey results: evidence from European professional forecasters

Using data from the ECB's Survey of Professional Forecasters, we investigate the reporting practices of survey participants by comparing their point predictions and the mean/median/mode of their probability forecasts. We find that the individual point predictions, on average, tend to be biased towards favourable outcomes: they suggest too high growth and too low inflation rates. Most importantly, for each survey round, the aggregate survey results based on the average of the individual point predictions are also biased. These findings cast doubt on combined survey measures that average individual point predictions. Survey results based on probability forecasts are more reliable. JEL Classification: C42, E27, E47point estimates, subjective probability distributions, survey methods, Survey of Professional Forecasters (SPF)

Supersymmetry Breaking Warped Throats and the Weak Gravity Conjecture

We generalize the swampland criterion forbidding stable non-supersymmetric AdS vacua and propose a new swampland conjecture forbidding stable non-supersymmetric "locally AdS" warped throats. The conjecture is motivated by the properties of systems of fractional D3-branes at singularities, and can be used to rule out large classes of warped throats with supersymmetry breaking ingredients, and their possible application to de Sitter uplift. In particular, this allows to reinterpret the runaway instabilities of the gravity dual of fractional branes in the dP$_1$ theory, and to rule out warped throats with Dynamical Supersymmetry Breaking D-brane sectors at their bottom. We also discuss the instabilities of warped throats with supersymmetry broken by the introduction of anti-orientifold planes. These examples lead to novel decay mechanisms in explicit non-supersymmetric examples of locally AdS warped throats, and also of pure AdS backgrounds.Comment: v4, 28 pages, refs adde