In Dummit and Foote section 7.4 Exercise 15 reads as follows:

"Let $\displaystyle x^2 + x + 1 $ be an element of the polynomial ring $\displaystyle E = {\mathbb{F}_2 [x] $ ... ..."

I am unsure of the meaning of the notation $\displaystyle {\mathbb{F}_2 $ - can someone please help?

Peter