The maximum size of a partial spread in H(5, q²) is q³+1

AbstractIn this paper, we show that the largest maximal partial spreads of the hermitian variety H(5,q2) consist of q3+1 generators. Previously, it was only known that q4 is an upper bound for the size of these partial spreads. We also show for q⩾7 that every maximal partial spread of H(5,q2) contains at least 2q+3 planes. Previously, only the lower bound q+1 was known

Urban Growth Boundaries: An Effective Second-Best Remedy for Unpriced Traffic Congestion?

This paper evaluates the efficacy of the urban growth boundary (UGB) as a second-best substitute for a first-best toll regime in a congested city. Numerical results show that, while a UGB is welfare improving, validating previous theoretical results, the utility gain it generates is a very small fraction of that achieved under a toll regime. Thus, the UGB is not a useful instrument for attacking the distortions caused by unpriced traffic congestion.

Partial Fiscal Decentralization

The fiscal decentralization impulse now sweeping the world often leads to partial decentralization, where subnational governments are funded by central transfers, rather than leading to full local autonomy. Despite the practical important of this arrangement, the literature contains no economic analysis of a partial decentralization regime in a Tiebout-style model. This paper provides such an analysis, relying on the key assumption that public-good provision requires effort on the part of government officials. By choosing different degrees of effort, localities can then provide different public-good levels even when a fixed, common transfer constrains them to spend the same amount. A number of useful results are derived.

Characterizations of boundary pluripolar Hulls

We present some basic properties of the boundary relative extremal function and discuss so called boundary pluripolar sets and boundary pluripolar hulls. We show that for B-regular domains the boundary pluripolar hull is always trivial on the boundary of the domain and present a "boundary version" of Zeriahi's theorem on the completeness of pluripolar sets.Comment: 9 pages, In this version some small changes were made and a few typo's were corrected. Version 3 has 10 pages. Section 2 has been rewritten. It now includes observations about different versions of the boundary extremal function as introduced by Sadullaev. We removed superfluous assumptions in some of the statement

Transport Subsidies, System Choice, and Urban Sprawl

This paper analyzes the effect of transport subsidies on the spatial expansion of cities, asking whether subsidies are a source of undesirable urban sprawl. While the cost-reducing effect of transport subsidies is offset by a higher general tax burden (which reduces the demand for space), the analysis shows that subsidies nevertheless lead to spatial expansion of cities. If the transport system exhibits constant returns to scale, the subsidies are inefficient, making the urban expansion they entail undesirable. The paper also studies transport ‘system choice.’ The city is portrayed as selecting its transport system from along a continuum of money-cost/time-cost choices.transport subsidies, urban sprawl, spatial expansion of cities, transport, urban expansion

Slot-Based Approaches to Airport Congestion Management

This paper analyzes slot-based approaches to management of airport congestion, using a model where airlines are asymmetric and internalize airport congestion. Under these circumstances, optimal congestion tolls differ across carriers, and since a slot-sale regime (with its uniform slot price) cannot duplicate this pattern, the equilibrium it generates is inefficient. Flight volumes tend to be too low for large carriers and too high for small carriers. Under a slot-trading regime or a slot auction, however, the existence of a fixed number of slots causes carriers to treat total flight volume (and thus congestion) as fixed, and this difference can lead to an efficient outcome.

Partial Fiscal Decentralization

The fiscal decentralization impulse now sweeping the world often leads to partial decentralization, where subnational governments are funded by central transfers, rather than leading to full local autonomy. Despite the practical important of this arrangement, the literature contains no economic analysis of a partial decentralization regime in a Tiebout-style model. This paper provides such an analysis, relying on the key assumption that public-good provision requires effort on the part of government officials. By choosing different degrees of effort, localities can then provide different public-good levels even when a fixed, common transfer constrains them to spend the same amount. A number of useful results are derived.Decentralization; Tiebout