reserve c for Complex;
reserve r for Real;
reserve m,n for Nat;
reserve f for complex-valued Function;
reserve f,g for differentiable Function of REAL,REAL;
reserve L for non empty ZeroStr;
reserve x for Element of L;

theorem Th26:
  n+1 is_at_least_length_of seq(n,x)
  proof
    let i be Nat such that
A1: i >= n+1;
    n+0 < n+1 by XREAL_1:8;
    hence seq(n,x).i = (0_.L).i by A1,FUNCT_7:32
    .= 0.L by ORDINAL1:def 12,FUNCOP_1:7;
  end;
