George M. Bergman Coproducts and some universal ring constructions, Trans. A.M.S. 200 (1974) 33-88

P.43: In the display, the equation defining  P2  should be:  P2 = Im(1-e) = Ker(e). 

P.50: The last line ("nonzero powers ...") should instead be the last line on p.51. 

P.52: In the third line of the proof of Theorem 6.4, the statement that direct limits respect the property of being semihereditary is incorrect; see [35, Example 4.2].  However [35, Theorem 3.4] leads to a stronger result than that of the abovementioned theorem; namely, that Theorem 6.2 holds without the finite generation condition. 

Pp.68-75, sections 10-11: most of the questions raised in these sections are answered in [35]. 

Notes on the other papers listed below: [34] is closely related to [35], though the latter does not depend on it.  [36] gives an example stronger than that of Example 10.2 of this paper, which also answers the question in the paragraph before that example.  [37] inter alia corrects an error in [18]. 

Additional references (continuing numbering in paper)

[34] George M. Bergman and Warren Dicks, On universal derivations, J. Alg. 36 (1975) 193-211.  MR52#8196. 

[35] George M. Bergman and Warren Dicks, Universal derivations and universal ring constructions, Pacific J. Math. 79 (1978) 293-337. MR81b:16024. 

[36] Robert A. Indik, A PI-algebra which is not PI when an inverse is adjoined, Proc. A. M. S. 76 (1979) 11-13. MR80d:16015. 

[37] P. M. Cohn and Warren Dicks, Localization in semifirs, II, J. London Math. Soc.  (2) 13 (1976) 411-418. MR54#12814. 

Back to publications-list