On the double Lusin condition and convergence theorem for Kurzweil-Henstock type integrals

• Main Authors: Abraham Racca, Emmanuel Cabral
• Format: Article
• Language: English
• Published: Institute of Mathematics of the Czech Academy of Science 2016-07-01
• Series: Mathematica Bohemica
• Subjects: Kurzweil-Henstock integral; $g$-integral; double Lusin condition; uniform double Lusin condition
• Online Access: http://mb.math.cas.cz/full/141/2/mb141_2_4.pdf

Equiintegrability in a compact interval $E$ may be defined as a uniform integrability property that involves both the integrand $f_n$ and the corresponding primitive $F_n$. The pointwise convergence of the integrands $f_n$ to some $f$ and the equiintegrability of the functions $f_n$ together imply that $f$ is also integrable with primitive $F$ and that the primitives $F_n$ converge uniformly to $F$. In this paper, another uniform integrability property called uniform double Lusin condition introduced in the papers E. Cabral and P. Y. Lee (2001/2002) is revisited. Under the assumption of pointwise convergence of the integrands $f_n$, the three uniform integrability properties, namely equiintegrability and the two versions of the uniform double Lusin condition, are all equivalent. The first version of the double Lusin condition and its corresponding uniform double Lusin convergence theorem are also extended into the division space.