I have zero background and I have never seen these symbols before. Can someone explain what is going on here?
In a simple explanation: A finite field, is a finite set, meaning multiplication, addition, subtraction and division are defined and follow the rules of field axioms. It contains a finite number of elements. A basic example of Finite Fields are
p = prime
modulo P
If you are looking for more information, regarding programming with Finite Fields
See this source: https://jeremykun.com/2014/03/13/programming-with-finite-fields/
It might seem a bit wild, but if you read more about it, it will start to make sense. I'd also research into Finite Field Arithmetic.
I hope my answer was useful - yosh