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		6.33 Definition Let .

		(a) M TxtExta-identifies L (written: ) just in case .

		(b) .

		Intuitively, a scientist M TxtExta-identifies L just in case M, fed any text for L, semantically converges to indexes for some fixed a-variant of L. Clearly, TxtBc = TxtExt0.

		(a) Show that .

		(b) Show that .

		(c) Is ?

		6-11 Consider the following variation on identification in which b is the exact number of indexes to which a scientist is required to converge.

		6.34 Definition Let and .

		(a) (written: ) just in case for each text T for L there exists a nonempty finite set D such that the following hold:

		1. card(D) = b,

		2. for each , Wi =a L,

		3. for all but finitely many n, , and

		4. for each , there are infinitely many n such that M(T[n]) = i.

		(b) .

		Answer the following questions.

		(a) Show that for and , .

		(b) Analogous to the above definition, define the criteria in which the parameter a is now the exact number of errors made by each of the b indexes. Show that for and ,.

		6-12 Show that . Then, observe as a corollary that for , .