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@@ -7838,7 +7838,7 @@ <h2 id="Idea">Idea<a class="anchor-link" href="#Idea">¶</a></h2><p>Consider the
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@@ -7872,7 +7872,7 @@ <h2 id="Curvature">Curvature<a class="anchor-link" href="#Curvature">¶</a></h2>
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@@ -7894,10 +7894,12 @@ <h3 id="Scalar-Curvature">Scalar Curvature<a class="anchor-link" href="#Scalar-C
78947894\end{align}
78957895The second order central differential is</ p >
78967896< p > \begin{align}
7897- \frac{1}{2\tau}(\partial_a f - f\partial_a ) = \frac{1}{\tau}\partial_a \wedge f
7897+ \partial_a \wedge f \equiv \frac{1}{2}(\partial_a f - f\partial_a ) =
7898+ \frac{f(x+\tau a ) -2f(x)+ f(x-\tau a )}{2 \tau}
78987899
7899- \end{align}</ p >
7900- < p > what is
7900+ \end{align}
7901+ Note that these operations are all grade-perserving, so the usuall interpretation of the inner/outer product as grade changing is not sustained.
7902+ what is
79017903\begin{align}
79027904\partial_a f \partial_a \\
79037905\end{align}</ p >
@@ -7906,6 +7908,16 @@ <h3 id="Scalar-Curvature">Scalar Curvature<a class="anchor-link" href="#Scalar-C
79067908e^{\tau \partial_a} fe^{-\tau \partial_a} &=T_{\tau a}f \tilde T_{\tau a}
79077909
79087910\end{align}</ p >
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79097921< h3 id ="Exponetial-of-a--Differential "> Exponetial of a Differential< a class ="anchor-link " href ="#Exponetial-of-a--Differential "> ¶</ a > </ h3 > < p > \begin{align}
79107922\partial_a f &\equiv \frac{f(x+\tau a )- f(x)}{\tau} \\
79117923\partial_a f&= \frac{1}{\tau}(T_{\tau a}-1)f \\
@@ -7922,7 +7934,31 @@ <h3 id="Exponetial-of-a--Differential">Exponetial of a Differential<a class="an
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7944+ < h3 id ="Domain-vs-Range "> Domain vs Range< a class ="anchor-link " href ="#Domain-vs-Range "> ¶</ a > </ h3 > < p > how do we know if an operator will operator on the range of domain.</ p >
7945+ < p > For example take $f = x^2$
7946+ $T_a f(x) = f(x)+a = x^2 +a $</ p >
7947+ < h3 id ="Rotations-vs-Translations "> Rotations vs Translations< a class ="anchor-link " href ="#Rotations-vs-Translations "> ¶</ a > </ h3 > < p > Given that we defined the a-derivative applied to $f$ as,
7948+ $$ \partial_a f \equiv \frac{f(x+\tau a )- f(x)}{\tau} = \frac{1}{\tau}(T_{\tau a}-1)f $$</ p >
7949+ < p > Where $T$ is the translation operator. If we want to make a large translation, $a$ , we could add up many small translations.</ p >
7950+ < p > $$ T_a = \prod (T_{\tau a})^{\frac{1}{\tau}}
7951+ = (e^{ \tau \partial_a })^\frac{1}{\tau} = e^{ \partial_a }$$
7952+ Maybe the use of translation in the differential could be extended to rotations. so the finite diff would become a finite div.</ p >
7953+ < p > $$e^{\tau \partial_B} =R_{\tau B} $$</ p >
7954+ < p > where B is a bivector. Then we get</ p >
7955+ < p > $$ \nabla = \sum B \partial_B $$
7956+ $$ \nabla = e^{B \tau \partial_B} =R_{\tau B} $$
7957+ The geometric derivative is then</ p >
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@@ -7937,7 +7973,7 @@ <h3 id="Exponetial-of-a--Differential">Exponetial of a Differential<a class="an
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@@ -7948,7 +7984,7 @@ <h2 id="Ortho-not-Normal">Ortho-not-Normal<a class="anchor-link" href="#Ortho-no
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@@ -7958,7 +7994,7 @@ <h2 id="Curvature--on-a-sphere">Curvature on a sphere<a class="anchor-link" hre
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@@ -7995,7 +8031,7 @@ <h2 id="Curvature--on-a-sphere">Curvature on a sphere<a class="anchor-link" hre
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@@ -8026,7 +8062,7 @@ <h2 id="Others">Others<a class="anchor-link" href="#Others">¶</a></h2><p>How ca
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