for I being non degenerated commutative domRing-like Ring
for x being Element of (the_Field_of_Quotients I) st x <> 0. (the_Field_of_Quotients I) holds
for a being Element of I st a <> 0. I holds
for u being Element of Q. I st x = QClass. u & u = [a,(1. I)] holds
for v being Element of Q. I st v = [(1. I),a] holds
x " = QClass. v