Let
and
, and
be integers such that
,
, and
is absolutely integrable over
. Then with the
notation of §24.2(iii)
where
Let
denote the class of functions that have
continuous
derivatives on
and are polynomials of degree at most
in each
interval
,
. The members of
are called
cardinal spline functions. The functions

are called Euler splines of degree
.
For each
,
is the unique bounded function such that
and
The function
is also optimal in a certain sense; see
Schoenberg (1971).
A function of the form
, with
is
called a cardinal monospline of degree
.
Again with the notation of §24.2(iii) define
is a monospline of degree
, and it follows from
(24.4.25) and (24.4.27) that
For each
the function
is also the unique cardinal
monospline of degree
satisfying (24.17.6), provided that
for some positive constant
.
For any
the function
is the unique cardinal monospline of degree
having the least supremum norm
on
(minimality property).
Bernoulli and Euler numbers and polynomials occur in: number theory via
(24.4.7), (24.4.8), and other identities involving
sums of powers; the Riemann zeta function and
-series (§25.15,
Apostol (1976), and Ireland and Rosen (1990)); arithmetic of
cyclotomic fields and the classical theory of Fermat’s last theorem
(Ribenboim (1979) and Washington (1997));
-adic analysis
(Koblitz (1984, Chapter 2)).