let K be Field; :: thesis: for n, i being Nat holds len (Base_FinSeq K,n,i) = n
let n, i be Nat; :: thesis: len (Base_FinSeq K,n,i) = n
len (Replace (n |-> (0. K)),i,(1. K)) = len (n |-> (0. K)) by FINSEQ_7:7
.= n by FINSEQ_1:def 18 ;
hence len (Base_FinSeq K,n,i) = n ; :: thesis: verum