there's a "canned" routine called testfont. use it with plain tex:

```
tex testfont
```

it will walk you through what it wants to test. the first question is what font you want.
the comprehensive symbols list should show you what fonts the asterisk is in (i'm pretty
sure there's one in `cmsy10`

). then you tell it what to do. the usual directive is

```
\table\bye
```

if you want to test another font, then respond `\table\vfill\eject\init`

and the "what font"
question will come up again. you can preview the result, or print it out for reference.
the indices on the top/bottom/sides of the table will identify the addresses of the cells,
which is what the last argument of `\DeclareMathSymbol`

wants.

You wrote:

There are two problems:

(1) Apparently, there is some "option clash" when I use the amsart
document class.

The reason there's an "option clash" is that the `amsmath`

package is already loaded by the `amsart`

document class; hence, it shouldn't be loaded a second time with options that weren't already specified the first time the package was loaded (in the present case, at the `\documentclass`

stage). To activate the options `nosumlimits`

and `intlimits`

, you must load them via the `\documentclass`

command:

```
\documentclass[nosumlimits,intlimits]{amsart}
```

(2) There is no "clash" with the article document class. But the
output does not agree with the stated outcome of the manual.

Recall that TeX has two math styles: "text style", also called "inline style", and "display style". The following MWE illustrates (i) the differences in the sizes of the integral signs in the two math styles and (ii) the effects that the commands `\int\limits`

and `\int\nolimits`

have in each of the two styles. Observe that the `amsmath`

package is loaded with the `intlimits`

option. As you can see from the ouput of this code, when in *inline math* style one must state `\int\limits`

explicily in order to get the limits set below/above the integral symbol even if the `intlimits`

option was specified. Conversely, when in *display math* style, the limits will always be set below/above the integral sign *unless* one specifies `\int\nolimits`

.

```
\documentclass{article}
\usepackage[intlimits]{amsmath}
\usepackage{booktabs,tabularx}
\newcolumntype{C}{X}
\begin{document}
Package \texttt{amsmath} loaded with \texttt{intlimits} option.
\begin{tabularx}{\textwidth}{@{}l *{3}{>{\raggedright\arraybackslash}X} @{}}
\toprule
Math style
& explicitly require side-set limits
& no explicit directive for positioning of limits
& explicitly require below\slash above limits\\ \midrule
Inline
& $\int\nolimits_0^1 f(x)\,dx$
& $\int_0^1 f(x)\,dx$
& $\int\limits _0^1 f(x)\,dx$ \\[3ex]
Display
& $\displaystyle \int\nolimits_0^1 f(x)\,dx$
& $\displaystyle \int_0^1 f(x)\,dx$
& $\displaystyle \int\limits _0^1 f(x)\,dx$ \\ \bottomrule
\end{tabularx}
\end{document}
```

Of course, when in inline math mode, one usually does *not* want the limits of integration to be typeset below/above the integral symbol, because one generally wants to keep the size of the math expressions compact so that the gaps between successive lines don't become too large. In contrast, in equations that are offset or displayed on a line by themselves, typesetting the limits of integration below and above the integral symbol may be a good choice, especially if the integrand is "large", e.g., if it contains a fractional expression.

## Best Answer

As the name implies,

`\smash`

takes its contents and prints it as if its height and depth were zero.The definition in LaTeX is carried over from the one in plain TeX, with a slight difference; I'll use the LaTeX one for ease of reference. The following refers to LaTeX 2018-12-01.

The macro distinguish if it is called in math mode or not. Note that, for efficiency, it doesn't read its argument at the outset. I'll assume the call is

`\smash{abq}`

. In math mode we getand we now need to look at

`\mathsm@sh`

:According to the working of

`\mathpalette`

, we get the equivalent ofIf the call is in text mode, we have

`\makesm@sh{abq}`

. Nowso we obtain

In both cases TeX has set the contents of box 0; now

`\finsm@sh`

does its jobThis sets the height and depth of box 0 to 0pt and typesets the box after initiating horizontal mode.

When you load

`amsmath`

the definition is basically the same, with the difference that an optional argument is allowed, which can be either`t`

or`b`

. With`t`

the last operation becomes onlyso the depth is preserved; conversely, with

`b`

LaTeX only doesand the height is preserved. This is accomplished by the redefinition (referring to

`amsmath.sty`

release 2018-12-01)You see that

`\finsm@sh`

is redefined each time to consist of the necessary bits.The conditional definition of

`\smash`

in`amsmath.sty`

is due to the fact that`\leavevmode@ifvmode`

has been added to LaTeX starting from version 2018-12-01 to initiate horizontal mode if found in vertical mode. In prior version of LaTeX this didn't happen, reflecting the same behavior as in plain TeX, where the definition is the same as in the LaTeX kernel, but without`\leavevmode@ifvmode`

, which is defined in the LaTeX kernel by