“Ghosts of Missionaries”

Ghosts of ghosts for second class constraints

When one uses the Dirac bracket, second class constraints become first class. Hence, they are amenable to the BRST treatment characteristic of ordinary first class constraints. This observation is the starting point of a recent investigation by Batalin and Tyutin, in which all the constraints are put on the same footing. However, because second class constraints identically vanish as operators ...

Benefits of bilingualism: Evidence from Mormon missionaries

Several studies have argued that learning a foreign language has the potential to increase the general cognitive ability and test scores of students. In this analysis, the Mormon missionary program is used to test whether or not students who were assigned to learn a foreign language performed better in college. The results indicate that the increase in GPA due to serving a Mormon mission is the...

Lecture Notes on Ghosts & Differential Ghosts

Lecture 10 on Differential Equations & Differential Invariants and Lecture 11 on Differential Equations & Proofs equipped us with powerful tools for proving properties of differential equations without having to solve them. Differential invariants (dI) [Pla10a, Pla12] prove properties of differential equations by induction based on the right-hand side of the differential equation, rather than i...

Missionaries and Cannibals in the Causal Calculator

A knowledge representation formalism is \elaboration tolerant" to the extent that it is convenient to modify a set of facts expressed in the formalism to take into account new phenomena or changed circumstances. John McCarthy illustrated this idea by deening 19 elaborations of the Missionaries and Cannibals Problem. We argue that, to a certain degree, the goal of elaboration tolerance is met by...

Muslims, Missionaries and Warlords in Northwestern China