Question: Why Latex generates non-printable characters?

 

restart;
V:=x->piecewise(0<=x and x<=a,0,infinity):
ic:=f(x,0)=piecewise(0<=x and x<=a,A*x*(a-x),0):
pde :=I*h*diff(f(x,t),t)=-h^2/(2*m)*diff(f(x,t),x$2) +V(x)*f(x,t):
sol:=pdsolve([pde,ic],f(x,t)) assuming a>0;
Latex(sol)

gives

f \! \left(x , t\right) = 
\left(\left\{\begin{array}{cc}A x \left(a -x \right) & 0\le x \le a  \\0 & \mathit{otherwise}  \end{array}\right.\right)+\left(\Mapleoverset{\infty}{\Mapleunderset{n =1}{\textcolor{gray}{\sum }}}\! \frac{t^{n} \left(\textbf{proc} (U) \\
\textbf{option} \,operator,\,arrow; \\
\mapleIndent{1} r-1 st I \ast (-1/2 \ast h\hat{~}{2} \ast m\hat{~}{-1} \ast \mathit{diff} (\mathit{diff} (U,\,x),\,x) + \mathit{piecewise} (0&lex \, \textbf{and} \, x&lea,\,0,\,infinity) \ast U) \ast h\hat{~}{-1}\\
\textbf{end\ proc};\right)^{\left(n \right)}\! \left(\left\{\begin{array}{cc}A x \left(a -x \right) & 0\le x \le a  \\0 & \mathit{otherwise}  \end{array}\right.\right)}{n !}\right)

Notice, non-printable characters. I think it should have been \ast there but it gives  st

Maple 2020.2 and Physics 897.

FYI, this is what latex() command gives


latex(sol)

f \left( x,t \right) =
\begin{cases}Ax \left( a-x \right)  & 0\leq x \land x\leq a\\0 & \text{otherwise}\end{cases}
+\sum _{n=1}^{\infty }{\frac {{t}^{n} \left( U\mapsto {\frac {-i
\begin{cases}0 & 0\leq x \land x\leq a\\\infty  & \text{otherwise}\end{cases}
U}{h}}^{ \left( n \right) } \right)  \left( 
\begin{cases}Ax \left( a-x \right)  & 0\leq x \land x\leq a\\0 & \text{otherwise}\end{cases}
 \right) }{n!}}

Which compiles with no problem

\documentclass[11pt]{article}
\usepackage{amsmath}
\begin{document}
\[
f \left( x,t \right) =
\begin{cases}Ax \left( a-x \right)  & 0\leq x \land x\leq a\\0 & \text{otherwise}\end{cases}
+\sum _{n=1}^{\infty }{\frac {{t}^{n} \left( U\mapsto {\frac {-i
\begin{cases}0 & 0\leq x \land x\leq a\\\infty  & \text{otherwise}\end{cases}
U}{h}}^{ \left( n \right) } \right)  \left( 
\begin{cases}Ax \left( a-x \right)  & 0\leq x \land x\leq a\\0 & \text{otherwise}\end{cases}
 \right) }{n!}}
\]
\end{document}

 

Thank you

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