2,279 research outputs found
Representing Code History with Development Environment Events
Modern development environments handle information about the intent of the
programmer: for example, they use abstract syntax trees for providing
high-level code manipulation such as refactorings; nevertheless, they do not
keep track of this information in a way that would simplify code sharing and
change understanding. In most Smalltalk systems, source code modifications are
immediately registered in a transaction log often called a ChangeSet. Such
mechanism has proven reliability, but it has several limitations. In this paper
we analyse such limitations and describe scenarios and requirements for
tracking fine-grained code history with a semantic representation. We present
Epicea, an early prototype implementation. We want to enrich code sharing with
extra information from the IDE, which will help understanding the intention of
the changes and let a new generation of tools act in consequence
Equilibrium Wage Dispersion: An Example
Search models with posting and match-specific heterogeneity generate wage dispersion. Given K values for the match-specific variable, it is known that there are K reservation wages that could be posted, but generically never more than two actually are posted in equilibrium. What is unknown is when we get two wages, and which wages are actually posted. For an example with K = 3, we show equilibrium is unique; may have one wage or two; and when there are two, the equilibrium can display any combination of posted reservation wages, depending on parameters. We also show how wages, profits, and unemployment depend on productivitySearch equilibrium, wage posting, wage dispersion, labor theory
Dirty black holes: Symmetries at stationary non-static horizons
We establish that the Einstein tensor takes on a highly symmetric form near
the Killing horizon of any stationary but non-static (and non-extremal) black
hole spacetime. [This follows up on a recent article by the current authors,
gr-qc/0402069, which considered static black holes.] Specifically, at any such
Killing horizon -- irrespective of the horizon geometry -- the Einstein tensor
block-diagonalizes into ``transverse'' and ``parallel'' blocks, and its
transverse components are proportional to the transverse metric. Our findings
are supported by two independent procedures; one based on the regularity of the
on-horizon geometry and another that directly utilizes the elegant nature of a
bifurcate Killing horizon. It is then argued that geometrical symmetries will
severely constrain the matter near any Killing horizon. We also speculate on
how this may be relevant to certain calculations of the black hole entropy.Comment: 21 pages; plain LaTe
Alternative Theories of Wage Dispersion
We analyze labor market models where the law of one price does not hold; i.e., models with equilibrium wage dispersion. We begin assuming workers are ex ante heterogeneous, and highlight a flaw with this approach: if search is costly, the market shuts down. We then assume workers are homogeneous but matches are ex post heterogeneous. This model is robust to search costs, and delivers equilibria equilibrium wage dispersion. However, we prove the law of two prices holds: generically we cannot get more than two wages. We explore several other models, including one combining ex ante and ex post heterogeneity; this model is robust, and can deliver more than two-point wage distributions.wages, search, distributions
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