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8 changes: 4 additions & 4 deletions src/content/3.11/kan-extensions.tex
Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@
If the Kan extension $F = Ran_{K}D$ exists, there must be a unique
natural transformation $\sigma$ from $F'$ to it, such
that $\varepsilon'$ factorizes through $\varepsilon$, that is:
\[\varepsilon' = \varepsilon\ .\ (\sigma \circ K)\]
\[\varepsilon' = \varepsilon \cdot (\sigma \circ K)\]
Here, $\sigma \circ K$ is the horizontal composition of two natural
transformations (one of them being the identity natural transformation
on $K$). This transformation is then vertically composed with
Expand Down Expand Up @@ -104,7 +104,7 @@ \section{Right Kan Extension}
there is a unique natural transformation
\[\sigma \Colon F' \to F\]
that factorizes $\varepsilon'$:
\[\varepsilon' = \varepsilon\ .\ (\sigma \circ K)\]
\[\varepsilon' = \varepsilon \cdot (\sigma \circ K)\]
This is quite a mouthful, but it can be visualized in this nice diagram:

\begin{figure}[H]
Expand Down Expand Up @@ -238,7 +238,7 @@ \section{Left Kan Extension}

\noindent
such that:
\[\eta' = (\sigma \circ K)\ .\ \eta\]
\[\eta' = (\sigma \circ K) \cdot \eta\]
This is illustrated in the following diagram:

\begin{figure}[H]
Expand All @@ -263,7 +263,7 @@ \section{Left Kan Extension}

As before, we can recast the one-to-one correspondence between natural
transformations:
\[\eta' = (\sigma \circ K)\ .\ \eta\]
\[\eta' = (\sigma \circ K) \cdot \eta\]
in terms of the adjunction:
\[[\cat{A}, \cat{C}](\Lan_{K}D, F') \cong [\cat{I}, \cat{C}](D, F' \circ K)\]
In other words, the left Kan extension is the left adjoint, and the
Expand Down
2 changes: 1 addition & 1 deletion src/content/3.12/enriched-categories.tex
Original file line number Diff line number Diff line change
Expand Up @@ -397,7 +397,7 @@ \section{Self Enrichment}
\[[b, c] \otimes ([a, b] \otimes a) \to [b, c] \otimes b\]
And use the counit $\varepsilon_{b c}$ again to get to $c$. We have
thus constructed a morphism:
\[\varepsilon_{b c}\ .\ (\idarrow[{[b, c]}] \otimes \varepsilon_{a b})\ .\ \alpha_{[b, c] [a, b] a}\]
\[\varepsilon_{b c} \circ (\idarrow[{[b, c]}] \otimes \varepsilon_{a b}) \circ \alpha_{[b, c] [a, b] a}\]
that is an element of the hom-set:
\[\cat{V}(([b, c] \otimes [a, b]) \otimes a, c)\]
The adjunction will give us the composition law we were looking for.
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8 changes: 4 additions & 4 deletions src/content/3.13/topoi.tex
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Expand Up @@ -58,7 +58,7 @@ \section{Subobject Classifier}
are equivalent if there is an isomorphism:
\[h \Colon a \to a'\]
such that:
\[f = f'\ .\ h\]
\[f = f' \circ h\]
Such a family of equivalent injections defines a subset of $b$.

\begin{figure}[H]
Expand All @@ -76,7 +76,7 @@ \section{Subobject Classifier}
g' & \Colon c \to a
\end{align*}
such that:
\[m\ .\ g = m\ .\ g'\]
\[m \circ g = m \circ g'\]
it must be that $g = g'$.

\begin{figure}[H]
Expand Down Expand Up @@ -142,8 +142,8 @@ \section{Subobject Classifier}

\noindent
Let's analyze this diagram. The pullback equation is:
\[\mathit{true}\ .\ \mathit{unit} = \chi\ .\ f\]
The function $\mathit{true}\ .\ \mathit{unit}$ maps every element of $a$ to
\[\mathit{true} \circ \mathit{unit} = \chi \circ f\]
The function $\mathit{true} \circ \mathit{unit}$ maps every element of $a$ to
``true.'' Therefore $f$ must map all elements of $a$ to
those elements of $b$ for which $\chi$ is ``true.'' These
are, by definition, the elements of the subset that is specified by the
Expand Down