let n, i be non zero Nat; for X being non-empty n + 1 -element FinSequence
for S being sigmaFieldFamily of X st i <= n holds
CarProduct (SubFin (X,i)) = CarProduct (SubFin ((SubFin (X,n)),i))
let X be non-empty n + 1 -element FinSequence; for S being sigmaFieldFamily of X st i <= n holds
CarProduct (SubFin (X,i)) = CarProduct (SubFin ((SubFin (X,n)),i))
let S be sigmaFieldFamily of X; ( i <= n implies CarProduct (SubFin (X,i)) = CarProduct (SubFin ((SubFin (X,n)),i)) )
assume A1:
i <= n
; CarProduct (SubFin (X,i)) = CarProduct (SubFin ((SubFin (X,n)),i))
n <= n + 1
by NAT_1:13;
hence
CarProduct (SubFin (X,i)) = CarProduct (SubFin ((SubFin (X,n)),i))
by A1, Th7; verum