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- .SC "Size and Font Changes"
- .PP
- 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.
- Although
- .UC EQN
- makes a valiant attempt to use
- esthetically pleasing sizes and fonts,
- it is not perfect.
- To change sizes and fonts, use
- .ul
- size n
- and
- .ul
- roman, italic,
- .ul
- bold
- and
- .ul
- fat.
- Like
- .ul
- sub
- and
- .ul
- sup,
- size
- and font changes affect only the thing that follows
- them, and revert to the normal situation
- at the end of it. Thus
- .P1
- bold x y
- .P2
- is
- .EQ
- bold x y
- .EN
- and
- .P1
- size 14 bold x = y +
- size 14 {alpha + beta}
- .P2
- gives
- .EQ
- size 14 bold x = y +
- size 14 {alpha + beta}
- .EN
- 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
- .P1
- size 12 { ... }
- .P2
- .PP
- Legal sizes which may follow
- .ul
- size
- are
- 6, 7, 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, 24, 28, 36.
- You can also change the size
- .ul
- by
- a given amount;
- for example, you can say
- .ul
- size~+2
- to make the size two points bigger,
- or
- .ul
- size~\(mi3
- to make it three points smaller.
- This has the advantage that you don't have
- to know what the current size is.
- .PP
- If you are using fonts other than roman, italic and bold,
- you can say
- .ul
- font X
- where
- .ul
- X
- is a one character
- .UC TROFF
- name or number for the font.
- Since
- .UC EQN
- is tuned for roman, italic and bold,
- other fonts may not give quite as good an appearance.
- .PP
- The
- .ul
- fat
- operation takes the current font and widens it by overstriking:
- .ul
- fat\ grad
- is
- $fat grad$ and
- .ul
- fat {x sub i}
- is
- $fat {x sub i}$.
- .PP
- 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
- equation.
- 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,
- .P1
- ^EQ
- gsize 16
- gfont R
- ...
- ^EN
- .P2
- to set the size to 16 and the font to roman thereafter.
- In place of R, you can use any of the
- .UC TROFF
- font names.
- The size after
- .ul
- gsize
- can be a relative change with + or \(mi.
- .PP
- Generally,
- .ul
- gsize
- and
- .ul
- gfont
- will appear at the beginning of a document
- but they can also appear
- thoughout a document: the global font and size
- can be changed as often as needed.
- For example, in a footnote\(dd
- .FS
- \(ddLike this one, in which we have a
- $gsize -2$few random
- expressions like $x sub i$ and $pi sup 2$.
- The sizes for these were set by the command
- .ul
- gsize~\(mi2.
- .FE $gsize +2$
- you will typically want the size of equations to match
- the size of the footnote text, which is two points smaller
- than the main text.
- Don't forget to reset the global size
- at the end of the footnote.
- .SC "Diacritical Marks"
- .PP
- To get funny marks on top of letters,
- there are several words:
- .P1
- .tr ^^
- .tr ~~
- .ta 1i
- x dot $x dot$
- x dotdot $x dotdot$
- x hat $x hat$
- x tilde $x tilde$
- x vec $x vec$
- x dyad $x dyad$
- x bar $x bar$
- x under $x under$
- .P2
- The diacritical mark is placed at the right height.
- The
- .ul
- bar
- and
- .ul
- under
- are made the right length for the entire construct,
- as in $x+y+z bar$;
- other marks are centered.
- .SC "Quoted Text"
- .PP
- 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:
- .P1
- italic "sin(x)" + sin (x)
- .P2
- is
- .EQ
- italic "sin(x)" + sin (x)
- .EN
- .PP
- Quotes are also used to get braces and other
- .UC EQN
- keywords printed:
- .P1
- "{ size alpha }"
- .P2
- is
- .EQ
- "{ size alpha }"
- .EN
- and
- .P1
- roman "{ size alpha }"
- .P2
- is
- .EQ
- roman "{ size alpha }"
- .EN
- .PP
- The construction "" is often used as a place-holder
- when grammatically
- .UC EQN
- needs something, but you don't actually want anything in your output.
- For example, to make
- $"" sup 2 roman He$,
- you can't just type
- .ul
- sup 2 roman He
- because a
- .ul
- sup
- has to be a superscript
- .ul
- on
- something.
- Thus you must say
- .P1
- "" sup 2 roman He
- .P2
- .PP
- To get a literal quote
- use ``\\"''.
- .UC TROFF
- characters like
- .ul
- \e(bs
- can appear unquoted, but more complicated things like
- horizontal and vertical motions with
- .ul
- \eh
- and
- .ul
- \ev
- should
- always
- be quoted.
- (If you've never heard of
- .ul
- \\h
- and
- .ul
- \\v,
- ignore this section.)
- .SC "Lining Up Equations"
- .PP
- 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
- .ul
- mark
- and
- .ul
- lineup.
- .PP
- The word
- .ul
- mark
- 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
- .ul
- lineup.
- The place where
- .ul
- lineup
- appears is made to line up
- with the place marked by the previous
- .ul
- mark
- if at all possible.
- Thus, for example,
- you can say
- .P1
- ^EQ I
- x+y mark = z
- ^EN
- ^EQ I
- x lineup = 1
- ^EN
- .P2
- to produce
- .EQ I
- x+y mark = z
- .EN
- .EQ I
- x lineup = 1
- .EN
- For reasons too complicated to talk about,
- when you use
- .UC EQN
- and
- `\(mims',
- use either
- .UC .EQ\ I
- or
- .UC .EQ\ L .
- mark
- and
- .ul
- lineup
- don't work with centered equations.
- Also bear in mind that
- .ul
- mark
- doesn't look ahead;
- .P1
- x mark =1
- ...
- x+y lineup =z
- .P2
- isn't going to work, because there isn't room
- for the
- .ul
- x+y
- part after the
- .ul
- mark
- remembers where the
- .ul
- x
- is.
- .SC "Big Brackets, Etc."
- .PP
- .tr ~
- To get big brackets [~],
- braces {~}, parentheses (~), and bars |~|
- around things, use the
- .ul
- left
- and
- .ul
- right
- commands:
- .tr ~~
- .P1
- left { a over b + 1 right }
- ~=~ left ( c over d right )
- + left [ e right ]
- .P2
- is
- .EQ
- left { a over b + 1 right } ~=~ left ( c over d right ) + left [ e right ]
- .EN
- 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.
- One exception is the
- .ul
- floor
- and
- .ul
- ceiling
- characters:
- .P1
- left floor x over y right floor
- <= left ceiling a over b right ceiling
- .P2
- produces
- .EQ
- left floor x over y right floor
- <= left ceiling a over b right ceiling
- .EN
- .PP
- 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.
- .PP
- The
- .ul
- right
- part may be omitted:
- a ``left something'' need not have a
- corresponding
- ``right
- something''.
- If the
- .ul
- right
- part is omitted,
- put braces around the thing you want the left bracket
- to encompass.
- Otherwise, the resulting brackets may be too large.
- .PP
- If you want to omit the
- .ul
- left
- part, things are more complicated,
- because technically you can't have a
- .ul
- right
- without a corresponding
- .ul
- left.
- Instead you have to say
- .P1
- left "" ..... right )
- .P2
- for example.
- The
- .ul
- left ""
- means a ``left nothing''.
- This satisfies the rules without hurting your output.
- .SC "Piles"
- .PP
- There is a general facility for making vertical piles
- of things; it comes in several flavors.
- For example:
- .P1
- .tr ~~
- A ~=~ left [
- pile { a above b above c }
- ~~ pile { x above y above z }
- right ]
- .P2
- will make
- .EQ
- A ~=~ left [
- pile { a above b above c } ~~ pile { x above y above z }
- right ]
- .EN
- The elements of the pile (there can be as many as you want)
- are centered one above another, at the right height for
- most purposes.
- The keyword
- .ul
- above
- 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.
- .PP
- Three other forms of pile exist:
- .ul
- lpile
- makes a pile with the elements left-justified;
- .ul
- rpile
- makes a right-justified pile;
- and
- .ul
- cpile
- makes a centered pile, just like
- .ul
- pile.
- The vertical spacing between the pieces
- is somewhat larger for
- .ul
- l-,
- .ul
- r-
- and
- .ul
- cpiles
- than it is for ordinary piles.
- .P1 2
- roman sign (x)~=~
- left {
- lpile {1 above 0 above -1}
- ~~ lpile
- {if~x>0 above if~x=0 above if~x<0}
- .P2
- makes
- .EQ
- roman sign (x)~=~
- left {
- lpile {1 above 0 above -1}
- ~~ lpile
- {if~x>0 above if~x=0 above if~x<0}
- .EN
- Notice the left brace
- without a matching right one.
- .SC Matrices
- .PP
- It is also possible to make matrices.
- For example, to make
- a neat array like
- .EQ
- matrix {
- ccol { x sub i above y sub i }
- ccol { x sup 2 above y sup 2 }
- }
- .EN
- you have to type
- .P1
- matrix {
- ccol { x sub i above y sub i }
- ccol { x sup 2 above y sup 2 }
- }
- .P2
- This produces a matrix with
- two centered columns.
- The elements of the columns are then listed just as for a pile,
- each element separated by the word
- .ul
- above.
- You can also use
- .ul
- lcol
- or
- .ul
- rcol
- to left or right adjust columns.
- Each column can be separately adjusted,
- and there can be as many columns as you like.
- .PP
- 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
- spacing to use.
- .PP
- A word of warning about matrices _
- .ul
- each column must have the same number of elements in it.
- The world will end if you get this wrong.
-