In this paper we propose some very promissing results in interval arithmetics
which permit to build well-defined arithmetics including distributivity of
multiplication and division according addition and substraction. Thus, it
allows to build all algebraic operations and functions on intervals. This will
avoid completely the wrapping effects and data dependance. Some simple
applications for matrix eigenvalues calculations, inversion of symmetric
matrices and finally optimization are exhibited in the object-oriented
programming language python.
In this paper we present the set of intervals as a normed vector space. We
define also a four-dimensional associative algebra whose product gives the
product of intervals in any cases. This approach allows to give a notion of
divisibility and in some cases an euclidian division. We introduce differential
calculus and give some applications.
The notion of $n$-ary algebras, that is vector spaces with a multiplication
concerning $n$-arguments, $n \geq 3$, became fundamental since the works of
Nambu. Here we first present general notions concerning $n$-ary algebras and
associative $n$-ary algebras. Then we will be interested in the notion of
$n$-Lie algebras, initiated by Filippov, and which is attached to the Nambu
algebras. We study the particular case of nilpotent or filiform $n$-Lie
algebras to obtain a beginning of classification.