Strong Hohmann transfer theorem

1995 ◽  
Vol 18 (2) ◽  
pp. 371-373 ◽  
Author(s):  
Fuyin Yuan ◽  
Koichi Matsushima
2009 ◽  
Vol 65 (7-8) ◽  
pp. 1094-1097 ◽  
Author(s):  
Badaoui El Mabsout ◽  
Osman M. Kamel ◽  
Adel S. Soliman
Keyword(s):  

Author(s):  
George Voutsadakis

The theory of equivalential deductive systems, as introduced by Prucnal and Wrónski and further developed by Czelakowski, is abstracted to cover the case of logical systems formalized as π-institutions. More precisely, the notion of an N-equivalence system for a given π-institution is introduced. A characterization theorem for N-equivalence systems, previously proven for N-parameterized equivalence systems, is revisited and a “transfer theorem” for N-equivalence systems is proven. For a π-institution I having an N-equivalence system, the maximum such system is singled out and, then, an analog of Herrmann’s Test, characterizing those N-protoalgebraic π-institutions having an N-equivalence system, is formulated. Finally, some of the rudiments of matrix theory are revisited in the context of π-institutions, as they relate to the existence of N-equivalence systems.


Author(s):  
Cyril Nicaud ◽  
Pablo Rotondo

In this article, we study some properties of random regular expressions of size [Formula: see text], when the cardinality of the alphabet also depends on [Formula: see text]. For this, we revisit and improve the classical Transfer Theorem from the field of analytic combinatorics. This provides precise estimations for the number of regular expressions, the probability of recognizing the empty word and the expected number of Kleene stars in a random expression. For all these statistics, we show that there is a threshold when the size of the alphabet approaches [Formula: see text], at which point the leading term in the asymptotics starts oscillating.


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