hmemcpy/milewski-ctfp-pdf
1
1
Fork 0
mirror of https://github.com/hmemcpy/milewski-ctfp-pdf.git synced 2024-11-26 03:11:47 +03:00
Code Issues Projects Releases Wiki Activity

Update representable-functors.tex

Browse Source
This commit is contained in:
Bartosz Milewski 2020-03-27 08:46:31 -07:00
parent 5e605c7a6e
commit 5b52ac6828
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/content/2.4/representable-functors.tex
View File

@ -202,8 +202,8 @@ It must respect naturality conditions, and it must be the inverse of \code{alpha
alpha . beta = id = beta . alpha
\end{snip}
We will see later that a natural transformation from $\cat{C}(a, -)$
to any $\Set$-valued functor always exists (Yoneda's lemma) but it
is not necessarily invertible.
to any $\Set$-valued functor always exists as long as $F a$ is
non-empty (Yoneda's lemma) but it is not necessarily invertible.
Let me give you an example in Haskell with the list functor and
\code{Int} as \code{a}. Here's a natural transformation that does