Let L be a recursive language. Let S(L) be the set of
L-structures with domain Ο. Let Ξ¦:Ο2βS(L) be a Ξ11β function with the property that
for all x,yβΟ2, Ο1xβ=Ο1yβ if and only if
Ξ¦(x)βLβΞ¦(y). Then there is some xβΟ2
so that SR(Ξ¦(x))=Ο1xβ+1