FOM: Re: Soare on "recursion" versus "computability"

Roger Bishop Jones rbjones at
Sun Aug 23 09:30:54 EDT 1998

>Date: Tue, 18 Aug 1998 17:08:47 -0400 (EDT)
>From: Stephen G Simpson <simpson at>
>Subject: FOM: what is computability theory?

>A few years ago, a group of recursion theorists decided to repackage
>their subject as "computability theory".  But what is computability
>theory?  I think I know what recursion theory is: it's the subject
>that I learned from Hartley Rogers and Gerald Sacks: relative
>recursiveness, degrees of unsolvability, recursively enumerable sets.
>My question now is, is computability theory the same subject, or a
>different one, or perhaps a broader one?

I don't understand your problem here Steve.
It seems to me clear from Soare's 95 paper that he is proposing
that the term "computability theory" should be used for what has hitherto
been called "recursion theory".  He says so in plain English.

As an outside observer I think this makes lot of sense.

If I had a vote I would cast it in favour.

Roger Jones

Affiliation (for what its worth): Roger Bishop Jones Limited
(see web site for a rambling clue about interests and competence)

email: rbjones at   www:

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