Published online by Cambridge University Press: 18 May 2009
A fundamental problem in the theory of ordinals is the assignation of principal sequences to limit numbers of the second number class.
It is our main object here to show that a certain class of methods, which are a natural generalisation of those used in the solution of the corresponding problem for the real numbers (the description of which we omit), must fail to solve the problem. The methods are those which rest on the following assumption: the principal sequence assigned to any limit number of the second number class is determined once the first i terms of that sequence are known.