Prime Subfield
The prime subfield of a field F is the subfield of F generated by the multiplicative identity 1_F of F. It is isomorphic to either Q (if the field characteristic is 0), or the finite field F_p=Z/pZ (if the field characteristic is p).
See also
SubfieldExplore with Wolfram|Alpha
WolframAlpha
References
Dummit, D. S. and Foote, R. M. "Basic Theory of Field Extensions." §13.1 in Abstract Algebra, 3rd ed. Hoboken, NJ: Wiley, pp. 510-519, 2004.Referenced on Wolfram|Alpha
Prime SubfieldCite this as:
Weisstein, Eric W. "Prime Subfield." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PrimeSubfield.html