I hope someone can help me with understanding the Abel–Ruffini theorem, especially the connection to nested radicals. I do know the proof based on Galois theory, but I wondered if this text which is appended is really correct? It gives a complete different approach to the topic than Galois theory. I would be thankful if anyone could confirm that this text is completely correct or if not, point out mistakes that this person who wrote this text has made (bad English has made me suspicious).
Edit: The main argument seems to be that a radical of form described in equation (12) cannot be used to solve polynomials of degree 5 or higher. It is claimed that this is not possible, cause you cannot handle 5 degrees of freedom (a,b,c,d,e in x^5+ax^4+bx^3+cx^2+dx+e). The question remains if this reasoning is correct. For more details have a look at the text.
