[Haskell-cafe] Is there a name for this?

Ben Franksen ben.franksen at online.de
Mon Mar 9 15:26:42 UTC 2015

Albert Y. C. Lai wrote:
> On 2015-03-08 12:11 PM, Eric wrote:
>> In some sense it's a canonical instance of Foo; we could trivially
>> write a universal
>> > toFoo' :: Foo f => f -> Foo'
>> function.
> Choose one:
> Foo' is a free Foo
> Foo' is a limit of the diagram of Foo
> Foo' is a terminal object of the [sub]category of Foo

Interesting. Is the last variant how "free <whatever>" is usually defined? 
Or is it a coincidence that the two, well, coincide here? I remember I have 
seen other definitions that looked a lot less easy to understand.


More information about the Haskell-Cafe mailing list