TAMENESS AND FRAMES REVISITED

We study the problem of extending an abstract independence notion for types of singletons (what Shelah calls a good frame) to longer types. Working in the framework of tame abstract elementary classes, we show that good frames can always be extended to types of independent sequences. As an application, we show that tameness and a good frame imply Shelah’s notion of dimension is well-behaved, complementing previous work of Jarden and Sitton. We also improve a result of the first author on extending a frame to larger models.

Solar: Fine Structure of the Flare of 1968 June 9

A class 2 flare began on 1968 June 9 in the active region near 17°N 40°E, at about 00h15m U.T., maximum 00h37m, terminating about 02h30m. The event was recorded at Culgoora with the 5-inch flare-patrol and 12-inch chromo-spheric telescopes at solar diameters and frame intervals of 16 mm/10 s and 17 cm/3 s respectively. Both telescopes used Halle filters, pass bands about 0.5Å centred on Hα, and Duplopan 35 mm film. The seeing was mediocre, with occasional fairly good frames.