Selective Categories and Linear Canonical Relations

A construction of Wehrheim and Woodward circumvents the problem that compositions of smooth canonical relations are not always smooth, building a category suitable for functorial quantization. To apply their construction to more examples, we introduce a notion of highly selective category, in which only certain morphisms and certain pairs of these morphisms are "good". We then apply this notion to the category $\mathbf{SLREL}$ of linear canonical relations and the result ${\rm WW}(\mathbf{SLREL})$ of our version of the WW construction, identifying the morphisms in the latter with pairs $(L,k)$ consisting of a linear canonical relation and a nonnegative integer. We put a topology on this category of indexed linear canonical relations for which composition is continuous, unlike the composition in $\mathbf{SLREL}$ itself. Subsequent papers will consider this category from the viewpoint of derived geometry and will concern quantum counterparts

Trade Agreements, Political Economy and Endogenously Incomplete Contracts

We develop a political economy model of trade agreements following along the line of Grossman and Helpman (1995a) yet incorporating contracting costs, uncertainty and multiple policy instruments. We show that rent-seeking efforts do not affect tariff rates as they are offset by the substitution effect of domestic production subsidies. Similar to Horn et al (2010), we find the coexistence of uncertainty and contracting costs make optimal trade agreements incomplete contracts. Our model helps explain differential treatment on subsidies, countervailing duties, and the national treatment principle - all key provisions of the current WTO agreement.Trade agreement, political economy, contracting cost, uncertainty JEL Classification:, Agricultural and Food Policy, International Relations/Trade, Political Economy, Public Economics,

Multiple-sensor integration for efficient reverse engineering of geometry

This paper describes a multi-sensor measuring system for reverse engineering applications. A sphere-plate artefact is developed for data unification of the hybrid system. With the coordinate data acquired using the optical system, intelligent feature recognition and segmentation algorithms can be applied to extract the global surface information of the object. The coordinate measuring machine (CMM) is used to re-measure the geometric features with a small amount of sampling points and the obtained information can be subsequently used to compensate the point data patches which are measured by optical system. Then the optimized point data can be exploited for accurate reverse engineering of CAD model. The limitations of each measurement system are compensated by the other. Experimental results validate the accuracy and effectiveness of this data optimization approach