let n be Nat; :: thesis: for a being Integer
for i1, i2, i3 being Element of n holds { p where p is n -element XFinSequence of NAT : p . i1 = (a * (p . i2)) * (p . i3) } is diophantine Subset of (n -xtuples_of NAT)

let a be Integer; :: thesis: for i1, i2, i3 being Element of n holds { p where p is n -element XFinSequence of NAT : p . i1 = (a * (p . i2)) * (p . i3) } is diophantine Subset of (n -xtuples_of NAT)
let i1, i2, i3 be Element of n; :: thesis: { p where p is n -element XFinSequence of NAT : p . i1 = (a * (p . i2)) * (p . i3) } is diophantine Subset of (n -xtuples_of NAT)
defpred S1[ XFinSequence of NAT ] means 1 * ($1 . i1) = (a * ($1 . i2)) * ($1 . i3);
defpred S2[ XFinSequence of NAT ] means $1 . i1 = (a * ($1 . i2)) * ($1 . i3);
A1: for p being n -element XFinSequence of NAT holds
( S1[p] iff S2[p] ) ;
{ p where p is n -element XFinSequence of NAT : S1[p] } = { q where q is n -element XFinSequence of NAT : S2[q] } from HILB10_3:sch 2(A1);
hence { p where p is n -element XFinSequence of NAT : p . i1 = (a * (p . i2)) * (p . i3) } is diophantine Subset of (n -xtuples_of NAT) by HILB10_3:9; :: thesis: verum