### On a question of nearly minimal identification of functions

**Author: Sanjay Jain**

**Source: ***
Information Processing Letters* Vol. **70**, No. 3,
1999, 113 - 117.

**Abstract.**
Suppose A and B are classes of recursive functions. A is said to be an
m-cover (*-cover) for B, iff for each g B,
there exists an f A such
that f differs from g on at most m inputs (finitely many inputs). C, a
class of recursive functions, is a-immune iff C is infinite and every
recursively enumerable subclass of C has a finite a-cover. C is
a-isolated iff C is finite or a-immune.

Chen (1981) conjectured that every class of recursive functions that
is **MEx**^{*}_{m}-identifiable is *-isolated.
We refute this conjecture.

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