This note is a continuation of our former paper “Complexity of the r-query tautologies in the presence of a generic oracle” (Notre Dame J. Formal Logic 41 (2000)). We give a very short direct proof of the nonexistence of t-generic oracles, a result obtaind first by Dowd (Inform. and Comput. 96 (1992)). We also reconsitute a proof of Dowd’s result that the class of all r-generic oracles in his s...

In this paper we study the question assuming MA+¬CH does Sacks forcing or Laver forcing collapse cardinals? We show that this question is equivalant to question of what is the additivity of Marczewski’s ideal s. We give a proof that it is consistent that Sacks forcing collapses cardinals. On the other hand we show that Laver forcing does not collapse cardinals. Introduction Let S be Sacks perfe...

Auxiliary ventilation of the blind development heading in underground mines is one of the most challenging work activities amongst mining underground operations. The auxiliary forcing ventilation system provides positive pressure, cooling, controlling gas layering, and removing diesel fumes and dust levels from development headings, stopes, and services facilities. The effectiveness of the auxi...

tulip is one of the most important flowers to precocity. treatment of tulip bulbs with gibberellic acid reduces the forcing period in the greenhouse resulting energy saving and reduces the tulip’s physiological disorders. this study carried out about three tulip cultivars includes ‘lacourtine’, ‘yokohama’ and ‘red favourite’. the results showed that gibberellic acid reduced significantly stem l...