A completeness proof in full DDL

Krister Segerberg

DOI: http://dx.doi.org/10.12775/LLP.2001.005


Dynamic doxastic logicians — not a large community — have trodden gingerly within the area of full DDL or, as with the present author, have not trodden at all. However, the latter, after having written up the final version of [6], realised that the proof given in that paper for two varieties of basic DDL can be extended to cover full DDL; in fact, the «full» proof is simpler than the «basic» one. The extended proof is outlined in Section 1–3. In Section 4, the relationship to AGM is considered. Section 5 puts the importance of the proof into perspective.

This note — an extended abstract rather than a full-fledged paper — should be read as an appendix to [6]. Although some definitions are repeated here, many are not. Readers who require more detail are referred to [6], a copy of which they should have on hand.

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Financed by MNiSW on the basis of agreement no. 706/P-DUN/2018 (dated 10/05/18). Project 1: “Preparation of articles in English for eight editions of the journal Logic and Logical Philosophy over the period 2018–19; Vol. 27, No. 1–4 (2018), Vol. 28, No. 1–4 (2019)”; amount from the DUN grant: 64800 zł. Project 4: “Digitalisation of eight editions of the journal Logic and Logical Philosophy over the period 2018-19; Vol. 27, No. 1–4 (2018), Vol. 28, No. 1–4 (2019)”; amount from the DUN grant: 18600 zł.

ISSN: 1425-3305 (print version)
ISSN: 2300-9802 (electronic version)

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