# isField -- whether something is a field

## Synopsis

• Usage:
isField R
• Inputs:
• Outputs:
• , true if R was explicitly constructed as a field (no computation is done) and false otherwise

## Description

This function recognizes basic fields, Galois fields and fraction fields.
 i1 : isField QQ o1 = true i2 : isField CC_53 o2 = true i3 : isField GF(2,3) o3 = true i4 : isField(frac(QQ[x,y])) o4 = true
This function will not recognize other rings as fields.
 i5 : R = QQ[x]/(x^2+1) o5 = R o5 : QuotientRing i6 : isUnit x o6 = true i7 : isField R o7 = false i8 : F = toField R o8 = F o8 : PolynomialRing i9 : isField F o9 = true