let K be non empty non degenerated right_complementable distributive Abelian add-associative right_zeroed associative Field-like doubleLoopStr ; for v being Valuation of K st K is having_valuation holds
for x, y being Element of K
for x1, y1 being Element of (ValuatRing v) st x = x1 & y = y1 holds
x * y = x1 * y1
let v be Valuation of K; ( K is having_valuation implies for x, y being Element of K
for x1, y1 being Element of (ValuatRing v) st x = x1 & y = y1 holds
x * y = x1 * y1 )
set R = ValuatRing v;
set c = NonNegElements v;
assume A1:
K is having_valuation
; for x, y being Element of K
for x1, y1 being Element of (ValuatRing v) st x = x1 & y = y1 holds
x * y = x1 * y1
let x, y be Element of K; for x1, y1 being Element of (ValuatRing v) st x = x1 & y = y1 holds
x * y = x1 * y1
let x1, y1 be Element of (ValuatRing v); ( x = x1 & y = y1 implies x * y = x1 * y1 )
assume A2:
( x = x1 & y = y1 )
; x * y = x1 * y1
A3:
NonNegElements v = the carrier of (ValuatRing v)
by A1, Def12;
A4:
the multF of (ValuatRing v) = the multF of K | [:(NonNegElements v),(NonNegElements v):]
by A1, Def12;
thus x1 * y1 =
the multF of (ValuatRing v) . [x1,y1]
.=
x * y
by A3, A4, A2, FUNCT_1:49
; verum