Given the task definition and input, reply with output. In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Context: In 1979 Hirschfeld published the first of a trilogy on Galois geometry, pegged at a level depending only on "the group theory and linear algebra taught in a first degree course, as well as a little projective geometry, and a very little algebraic geometry. Link Information: ystems of linear equations arose in Europe with the introduction in 1637 by Rene Descartes of coordinates in geometry. Question: Of the types of math Hirschfeld in 1979 considered necessary to learn before reading his work on Galois geometry, which is the oldest mathematical discipline?
Answer: algebraic geometry