local

local s -- provides the local symbol s , creating a new symbol if necessary. The initial value of a local symbol is null .

     i1 = f = () -> ZZ[local t]
     
     o1 = f
     
     o1 : Function

     i2 = f()
     
     o2 = ZZ[$t]
     
     o2 : PolynomialRing

     i3 = t
     
     o3 = t
     
     o3 : Symbol