consider o being object such that
A: ( o in REAL & not o in RAT ) by NUMBERS:2, XBOOLE_0:6;
reconsider c = o as Element of F_Real by A;
thus not for b₁ being Element of F_Real holds b₁ is F_Rat -membered by A, FIELD_7:def 5, GAUSSINT:def 14; :: thesis: verum