Explore a comprehensive lecture on the existence and regularity theories of Brakke flow, presented by Yoshihiro Tonegawa from Tokyo Institute of Technology. Delve into key concepts such as introduction, definitions, characterization, subsidies, and geometric metatheory. Examine the approximate tangent space, integrals, and multiplicity function. Investigate vector field age, bracket law, and the concept of "for almost all time." Gain insights into this complex mathematical topic as part of the International School on Extrinsic Curvature Flows.