New Worlds, Lost Worlds

Anigraf6: Explorers new worlds

Anigraf6: Explorers new worlds

Adrian Miroiu WORLDS WITHIN WORLDS

It is sometimes argued that possible worlds are too rich. Indeed, for every sentence φ and every world w, either φ is true at w, or ¬φ is true at w. Possible worlds leave nothing unsettled: for any question one may ask, there is always an answer, yes or no. My view goes along the opposite side. I take possible worlds to be incredibly poor, and I think that a good deal can be added to them. The ...

Constructing Hereditary Worlds Within Worlds

Although they appear unrelated, the type system of the polymorphic λ-calculus with references and the assertions of concurrent separation logic with first-class locks share a critical feature: an unsound contravariant circularity in their naı̈ve semantic model. We developed indirection theory to automatically construct, and cleanly axiomatize, step-indexed approximations to these naı̈ve models, a...

New Worlds Observer Mission Design

New Worlds Observer is an external starshade mission designed to observe Earth-like planets around nearby stars. A telescope spacecraft operates in the “shadow” cast by a starshade spacecraft, located tens of thousands of kilometers away. We explore the requirements that these two free-flying spacecraft place on the orbital, propulsion, control, and communication systems and some baseline solut...