%0 Journal Article %T On the Lebesgue Integral and the Lebesgue Measure: Mathematical Applications in Some Sectors of Chern-Simons Theory and Yang-Mills Gauge Theory and Mathematical Connections with Some Sectors of String Theory and Number Theory %A Michele Nardelli %J Journal of Modern Physics %P 93-132 %@ 2153-120X %D 2025 %I Scientific Research Publishing %R 10.4236/jmp.2025.161004 %X In this paper, in Section 1, we have described some equations and theorems concerning the Lebesgue integral and the Lebesgue measure. In Section 2, we have described the possible mathematical applications, of Lebesgue integration, in some equations concerning various sectors of Chern-Simons theory and Yang-Mills gauge theory, precisely the two dimensional quantum Yang-Mills theory. In conclusion, in Section 3, we have described also the possible mathematical connections with some sectors of String Theory and Number Theory, principally with some equations concerning the Ramanujan’s modular equations that are related to the physical vibrations of the bosonic strings and of the superstrings, some Ramanujan’s identities concerning π and the zeta strings. %K Lebesgue Integral %K Chern-Simons Theory %K Yang-Mills Gauge Theory %K String Theory %K Number Theory %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=140069