Tracks, intersections and dead ends

Traps, Invariants, and Dead-Ends

We consider the problem of deriving formulas that capture traps, invariants, and dead-ends in classical planning through polynomial forms of preprocessing. An invariant is a formula that is true in the initial state and in all reachable states. A trap is a conditional invariant: once a state is reached that makes the trap true, all the states that are reachable from it will satisfy the trap for...

African Development: Dead Ends and New Beginnings

Frobenius Problem and Dead Ends in Integers

Let a and b be positive, relatively prime integers. We show that the following are equivalent: (i) d is a dead end in the (symmetric) Cayley graph of Z with respect to a and b, (ii) d is a Frobenius value with respect to a and b (it cannot be written as a non-negative or non-positive integer linear combination of a and b), and d is maximal (in the Cayley graph) with respect to this property. In...

Syntactic reconstruction and reanalysis, semantic dead ends, and prefrontal cortex.

The left inferior frontal gyrus (LIFG) is crucially has been found to be involved in syntactic processing of various kinds. This study investigates the cortical effects of two types of syntactic processes: (i) Reconstruction in ellipsis (recovery of left-out material given by context, More people have been to Paris than [...] to Oslo), using pseudo-elliptical structures ('dead ends') as control...

On Staying Grounded and Avoiding Quixotic Dead Ends

The 15 articles in this special issue on The Representation of Concepts illustrate the rich variety of theoretical positions and supporting research that characterize the area. Although much agreement exists among contributors, much disagreement exists as well, especially about the roles of grounding and abstraction in conceptual processing. I first review theoretical approaches raised in these...