Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Fundamenta Informaticae

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Variation Statistics on Compositions

Archibald M., Knopfmacher A., Mansour T.

Fundamenta Informaticae

2012

Vol. 117, nr 1-4

1-17

In this paper we consider the absolute variation statistics of a compositionσ=σ_1...σ_m of n which is a measure of the sum of absolute differences between each consecutive pair of parts in a composition. This and some related statistics which we discuss, can also be interpreted within the context of bargraph polygons and bargraph walks of area n. In this context, absolute variation corresponds to the interior vertical perimeter of a bargraph polygon or to the interior vertical length of a bargraph walk.

Randomness with Respect to the Signed-Digit Representation

Archibald M., Brattka V., Heuberger C.

Fundamenta Informaticae

2008

Vol. 83, nr 1-2

1-19

The ordinary notion of algorithmic randomness of reals can be characterised as Martin-Löf randomness with respect to the Lebesgue measure or as Kolmogorov randomness with respect to the binary representation. In this paper we study the question of how the notion of algorithmic randomness induced by the signed-digit representation of the real numbers is related to the ordinary notion of algorithmic randomness. We first consider the image measure on real numbers induced by the signed-digit representation. We call this measure the signed-digit measure and using the Fourier transform of this measure and the Riemann-Lebesgue Lemma we prove that this measure is not absolutely continuous with respect to the Lebesgue measure. We also show that the signed-digit measure can be obtained as a weakly convergent convolution of discrete measures and therefore, by the classical Theorem of Jessen and Wintner the Lebesgue measure is not absolutely continuous with respect to the signed-digit measure. Finally, we provide an invariance theorem which shows that if a computable map preserves Martin-Löf randomness, then its induced image measure has to be absolutely continuous with respect to the target space measure. This theorem can be considered as a loose analog for randomness of the Banach-Mazur theorem for computability. Using this Invariance Theorem we conclude that the notion of randomness induced by the signed-digit representation is incomparable with the ordinary notion of randomness.