Survey 1979: Equational Logic - Department of Mathematics ...
Survey 1979: Equational Logic - Department of Mathematics ...
Survey 1979: Equational Logic - Department of Mathematics ...
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EQUATIONAL LOGIC<br />
CONTENTS<br />
1. Early history and definitions ................................................... 1<br />
2. The existence <strong>of</strong> free algebras .................................................. 2<br />
3. <strong>Equational</strong>ly defined classes ................................................... 3<br />
4. Generation <strong>of</strong> varieties and subdirect representation ................................. 6<br />
5. <strong>Equational</strong> theories .......................................................... 8<br />
6. Examples <strong>of</strong> . ............................................................. 9<br />
7. Equivalent varieties .......................................................... 11<br />
8. Bases and generic algebras ..................................................... 14<br />
9. Finitely based theories ....................................................... !7<br />
10. One-based theories .......................................................... 21<br />
11. Irredundant bases ........................................................... 23<br />
12. Decidability questions ........................................................ 24<br />
13. The lattice <strong>of</strong> equational theories ............................................... 29<br />
MODEL THEORETIC QUESTIONS ............................................. 37<br />
14. Some further invariants <strong>of</strong> a variety ............................................. 37<br />
15. Malcev conditions and congruence identities ....................................... 45<br />
16. Connections with topology .................................................... 48<br />
17. Miscellaneous .............................................................. 49<br />
References ................................................................ 53