Re: Declaring super types

Reinier Post wrote:

>It wouldn't. Remove radius from Circles or add it
>to Elliupses, and these two particular instances will match,
>but in general it still won't be a case of "is-a" because
>in general, the same Circle may correspond to
>different Ellipses, which my second clause forbids.

PS: that is why Ellipse "is a" Circle will not hold. But Circle "is a" Ellipse will hold if Circle is given an axisX and axisY that always have the same value.

-- 
Reinier