Teacher:In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.
Teacher: Now, understand the problem? Solve this instance: Context: He received his doctoral degree on the basis of his dissertation on Lebesgue integrals and started to work as an academic teacher at his alma mater. Link Information: In mathematics, the integral of a non-negative function of a single variable can be regarded, in the simplest case, as the area between the graph of that function and the -axis.  Answer: the integral of a non-negative function of a single variable
Student:
What is Lebesgue integrals?