Am Mittwoch, 18. März 2009 15:17 schrieben Sie: > Wolfgang Jeltsch schrieb: > > Okay. Well, a monoid with many objects isn’t a monoid anymore since a > > monoid has only one object. It’s the same as with: “A ring is a field > > whose multiplication has no inverse.” One usually knows what is meant > > with this but it’s actually wrong. Wrong for two reasons: First, because > > the multiplication of a field has an inverse. Second, because the > > multiplication of a ring is not forced to have no inverse but may have > > one. > > “A ring is like a field, but without a multiplicative inverse” is, in my > eyes, an acceptable formulation. We just have to agree that “without” > here refers to the definition, rather than to the definitum.
Note that you said: “A ring is *like* a field.”, not “A ring is a field.” which was the formulation, I criticized above. Best wishes, Wolfgang _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
