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IV
Posts:
354
Registered:
9/1/11


Name and methods for the implicit algebraic numbers and functions?
Posted:
Sep 6, 2015 8:31 AM


Hallo.
1) We know that some polynomials have solutions, but their Galois groups are not solvable. Therefore there are algebraic numbers which cannot be explicitly described by an algebraic expression. 1a) Is there a name for this kind of algebraic numbers? 1b) Is there a method to construct or describe this kind of algebraic numbers only by symbolic methods, e.g. by closedform expressions?
2) We know, the defining algebraic equation of some algebraic functions has a solution, but the Galois group of the eqaution is not solvable. Therefore there are algebraic functions which cannot be explicitly described by an algebraic expression. 2a) Is there a name for this kind of algebraic functions? 2b) Is there a method to construct or describe this kind of algebraic functions only by symbolic methods, e.g. by closedform expressions?
3) Liouville and Ritt ("Integration in finite terms") define the class of elementary functions by algebraic equations over algebraic or transcendent monomials. Considering 1) and 2), this means that their class of elementary functions contains also the functions which are not expressible by an algebraic expression. This contradicts the normal use of the term "elementary function". 3a) Am I right? 3b) Has this incorrect definition of the class of elementary functions somewhere any consequences?
Thanks.



