Myself when young did eagerly frequent Doctor and Saint, and heard great Argument About it and about; but evermore Came out by the same Door as in I went. —Edward Fitzgerald: The Rubáiyát of Omar Khayyam The Third Manifesto, by Hugh Darwen and myself (&quot;the Manifesto &quot; for short), lays down a set of prescriptions and proscriptions regarding the design of a database programming language it calls D (see reference ). One prescription in particular—&quot;OO Prescription 3&quot;—reads as follows: D shall be computationally complete. That is, D may support, but shall not require, invocation from so-called host programs written in languages other than D. Similarly, D may support, but shall not require, the use of other languages for implementation of userdefined operators. However, reference  argues that this prescription implies that the Manifesto is deeply flawed. To quote: 1 It's an error to make Tutorial D computationally complete because it creates a language with logical expressions that are provably not decidable—yet a decision procedure must exist for any logical expression to be evaluated. Note: This quote refers to Tutorial D, not D as such, so I need to explain how Tutorial D relates to D. To begin with, the name D is generic—it's used in reference  to refer generically to any language that conforms to the principles laid down in The Third Manifesto. Thus, there could be any number of distinct languages all qualifying as a valid D. Tutorial D is intended to 1 For reasons of clarity and flow I've edited most of the quotes in this paper, sometimes drastically so. be one such; it's defined more or less formally in reference , and it's used throughout that book (and elsewhere) as a basis for examples. For definiteness I'll concentrate on Tutorial D myself (mostly) in the present paper, since that's what reference  does, but the discussions and arguments actually apply to any valid D. Decidabilit
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.