let m, n, k be non zero Nat; for X being non-empty m -element FinSequence
for S being sigmaFieldFamily of X
for M being sigmaMeasureFamily of S st k <= n & n <= m holds
ElmFin (M,k) = ElmFin ((SubFin (M,n)),k)
let X be non-empty m -element FinSequence; for S being sigmaFieldFamily of X
for M being sigmaMeasureFamily of S st k <= n & n <= m holds
ElmFin (M,k) = ElmFin ((SubFin (M,n)),k)
let S be sigmaFieldFamily of X; for M being sigmaMeasureFamily of S st k <= n & n <= m holds
ElmFin (M,k) = ElmFin ((SubFin (M,n)),k)
let M be sigmaMeasureFamily of S; ( k <= n & n <= m implies ElmFin (M,k) = ElmFin ((SubFin (M,n)),k) )
assume that
A1:
k <= n
and
A2:
n <= m
; ElmFin (M,k) = ElmFin ((SubFin (M,n)),k)
A3:
ElmFin (M,k) = M . k
by A1, A2, Def10, XXREAL_0:2;
1 <= k
by NAT_1:14;
then A4:
k in Seg n
by A1;
SubFin (M,n) = M | n
by A2, Def9;
then
ElmFin ((SubFin (M,n)),k) = (M | n) . k
by A1, Def10;
hence
ElmFin (M,k) = ElmFin ((SubFin (M,n)),k)
by A3, A4, FUNCT_1:49; verum