.SC "Size and Font Changes"
By default, equations are set in 10-point type (the same size as this guide),
with standard mathematical conventions
to determine what characters are in roman and what in italic.
makes a valiant attempt to use
esthetically pleasing sizes and fonts,
To change sizes and fonts, use
and font changes affect only the thing that follows
them, and revert to the normal situation
As always, you can use braces if you want to affect something
more complicated than a single letter.
For example, you can change the size of an entire equation by
Legal sizes which may follow
6, 7, 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, 24, 28, 36.
You can also change the size
to make the size two points bigger,
to make it three points smaller.
This has the advantage that you don't have
to know what the current size is.
If you are using fonts other than roman, italic and bold,
name or number for the font.
is tuned for roman, italic and bold,
other fonts may not give quite as good an appearance.
operation takes the current font and widens it by overstriking:
If an entire document is to be in a non-standard size
or font, it is a severe nuisance
to have to write out a size and font change for each
Accordingly, you can set a ``global'' size or font
which thereafter affects all equations.
At the beginning of any equation, you might say, for instance,
to set the size to 16 and the font to roman thereafter.
In place of R, you can use any of the
can be a relative change with + or \(mi.
will appear at the beginning of a document
thoughout a document: the global font and size
can be changed as often as needed.
For example, in a footnote\(dd
\(ddLike this one, in which we have a
expressions like $x sub i$ and $pi sup 2$.
The sizes for these were set by the command
you will typically want the size of equations to match
the size of the footnote text, which is two points smaller
Don't forget to reset the global size
at the end of the footnote.
To get funny marks on top of letters,
The diacritical mark is placed at the right height.
are made the right length for the entire construct,
other marks are centered.
Any input entirely within quotes (\|"..."\|)
is not subject to any of the font changes and spacing
adjustments normally done by the equation setter.
This provides a way to do your own spacing and adjusting if needed:
italic "sin(x)" + sin (x)
italic "sin(x)" + sin (x)
Quotes are also used to get braces and other
The construction "" is often used as a place-holder
needs something, but you don't actually want anything in your output.
can appear unquoted, but more complicated things like
horizontal and vertical motions with
(If you've never heard of
.SC "Lining Up Equations"
Sometimes it's necessary to line up a series of equations
at some horizontal position, often at an equals sign.
This is done with two operations called
may appear once at any place in an equation.
It remembers the horizontal position where it appeared.
Successive equations can contain one occurrence of the word
appears is made to line up
with the place marked by the previous
For reasons too complicated to talk about,
don't work with centered equations.
isn't going to work, because there isn't room
braces {~}, parentheses (~), and bars |~|
left { a over b + 1 right }
~=~ left ( c over d right )
left { a over b + 1 right } ~=~ left ( c over d right ) + left [ e right ]
The resulting brackets are made big enough to cover whatever they enclose.
Other characters can be used besides these,
but the are not likely to look very good.
left floor x over y right floor
<= left ceiling a over b right ceiling
left floor x over y right floor
<= left ceiling a over b right ceiling
Several warnings about brackets are in order.
First, braces are typically bigger than brackets and parentheses,
because they are made up of three, five, seven, etc., pieces,
while brackets can be made up of two, three, etc.
Second, big left and right parentheses often look poor,
because the character set is poorly designed.
a ``left something'' need not have a
put braces around the thing you want the left bracket
Otherwise, the resulting brackets may be too large.
part, things are more complicated,
because technically you can't have a
means a ``left nothing''.
This satisfies the rules without hurting your output.
There is a general facility for making vertical piles
of things; it comes in several flavors.
pile { a above b above c }
~~ pile { x above y above z }
pile { a above b above c } ~~ pile { x above y above z }
The elements of the pile (there can be as many as you want)
are centered one above another, at the right height for
is used to separate the pieces;
braces are used around the entire list.
The elements of a pile can be as complicated as needed, even containing more piles.
Three other forms of pile exist:
makes a pile with the elements left-justified;
makes a right-justified pile;
makes a centered pile, just like
The vertical spacing between the pieces
than it is for ordinary piles.
lpile {1 above 0 above -1}
{if~x>0 above if~x=0 above if~x<0}
lpile {1 above 0 above -1}
{if~x>0 above if~x=0 above if~x<0}
without a matching right one.
It is also possible to make matrices.
ccol { x sub i above y sub i }
ccol { x sup 2 above y sup 2 }
ccol { x sub i above y sub i }
ccol { x sup 2 above y sup 2 }
This produces a matrix with
The elements of the columns are then listed just as for a pile,
each element separated by the word
to left or right adjust columns.
Each column can be separately adjusted,
and there can be as many columns as you like.
The reason for using a matrix instead of two adjacent piles, by the way,
is that if the elements of the piles don't all have the same height,
they won't line up properly.
A matrix forces them to line up,
because it looks at the entire structure before deciding what
A word of warning about matrices _
each column must have the same number of elements in it.
The world will end if you get this wrong.