**ERRATUM.** In the original published version of Appendix 1, a number of the
equations were missing characters (principly minus signs). The corrected appendix
is provided in full below.

**Appendix 1 (corrected).** A formal statement of generosity rules.

* v _{ij}* = share of

where

The *symmetric generosity rule* occurs when

Walens (1981) reports that the Kwakiutl chief had to have completely empty
boxes at the end of a potlatch. In this case, we can define the *Kwakiutl
generosity rule,* which occurs when for each *i,j*,

Other generosity rules are of course possible. The pure selfishness, or private profit, rule would be: