st: Poisson model: how to impose restrictions on coefficients

[Sailangita@aol.com]

Dear All:

I need help on how to impose restrictions on coefficients.
I am running a poisson model like this:

Y =  a1 X1  +  a2 X2   + a3  X3  +  a4 X4   +  error term

I want to impose   a2 +  a3  = 1


Thanks in advance.


Diafuka
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