Hi all,

I wanted to discuss the project "Integrating factors for second order 
ODEs". First off, is the paper too big for a GSoC project this year since 
the time limit is reduced? If not, even parts of the paper can be 
implemented. I have already gone through the paper, and I have some doubts 
regarding it. 

1. For integrating factors of the form µ(x, y') in Section 2.2.1 Case B, 
the paper states that the integrating factor reduces to a search for µ(x) 
using the adjoint of the original ODE. Is this already implemented? If not, 
should it be considered as part of the project? If so, could someone 
suggest a good paper for this method?

2. In Section 2.2.3 Case A, how is F(x, y') being determined? What I think 
is the process - Factorize Υ and look for factors which contain y' but not 
y and take their reciprocal. But what if there are multiple factors? 
In the given example, there are no such factors, so Derivative(F(x, y'), 
y') = 1 which gives F(x, y') = y'. Please tell me if I understood it 
correctly.

3. I couldn't understand how to find F(x, y') in Section 2.2.3 Case B.

4. For integrating factors of the form µ(x, y') in Section 2.3, I couldn't 
understand how an integrating factor of 1/(y'**2*x) for the transformed ODE 
implies an integrating factor of 1/y for the original ODE. I tried applying 
the transformations x->y(x) and y(x)->x to the integrating factor, but I'm 
getting the integrating factor as y'**2/y.

Naveen

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