Tag  Description 
minimum_size 
eqn will not set anything at a smaller pointsize than this.
The value is in points.

fat_offset 
The
fat primitive emboldens an equation
by overprinting two copies of the equation
horizontally offset by this amount.

over_hang 
A fraction bar will be longer by twice this amount than
the maximum of the widths of the numerator and denominator;
in other words, it will overhang the numerator and
denominator by at least this amount.

accent_width 
When
bar or
under is applied to a single character,
the line will be this long.
Normally,
bar or
under produces a line whose length is the width of the object to which it applies;
in the case of a single character,
this tends to produce a line that looks too long.

delimiter_factor 
Extensible delimiters produced with the
left and
right primitives will have a combined height and depth of at least this many
thousandths of twice the maximum amount by which the subequation that
the delimiters enclose extends away from the axis.

delimiter_shortfall 
Extensible delimiters produced with the
left and
right primitives will have a combined height and depth
not less than the difference of
twice the maximum amount by which the subequation that
the delimiters enclose extends away from the axis
and this amount.

null_delimiter_space 
This much horizontal space is inserted
on each side of a fraction.

script_space 
The width of subscripts and superscripts is increased by this amount.

thin_space 
This amount of space is automatically inserted after punctuation
characters.

medium_space 
This amount of space is automatically inserted on either side
of binary operators.

thick_space 
This amount of space is automatically inserted on either side of
relations.

x_height 
The height of lowercase letters without ascenders such as x.

axis_height 
The height above the baseline of the center of characters
such as + and .
It is important that this value is correct for the font
you are using.

default_rule_thickness 
This should set to the thickness of the
\(ru character, or the thickness of horizontal lines produced with the
\D escape sequence.

num1 
The
over command will shift up the numerator by at least this amount.

num2 
The
smallover command will shift up the numerator by at least this amount.

denom1 
The
over command will shift down the denominator by at least this amount.

denom2 
The
smallover command will shift down the denominator by at least this amount.

sup1 
Normally superscripts will be shifted up by at least this amount.

sup2 
Superscripts within superscripts or upper limits
or numerators of
smallover fractions
will be shifted up by at least this amount.
This is usually less than sup1.

sup3 
Superscripts within denominators or square roots
or subscripts or lower limits will be shifted up by at least
this amount.
This is usually less than sup2.

sub1 
Subscripts will normally be shifted down by at least this amount.

sub2 
When there is both a subscript and a superscript, the subscript
will be shifted down by at least this amount.

sup_drop 
The baseline of a superscript will be no more
than this much amount below the top of the object on
which the superscript is set.

sub_drop 
The baseline of a subscript will be at least this much below
the bottom of the object on which the subscript is set.

big_op_spacing1 
The baseline of an upper limit will be at least this
much above the top of the object on which the limit is set.

big_op_spacing2 
The baseline of a lower limit will be at least this
much below the bottom of the object on which the limit is set.

big_op_spacing3 
The bottom of an upper limit will be at least this much above the
top of the object on which the limit is set.

big_op_spacing4 
The top of a lower limit will be at least this much below
the bottom of the object on which the limit is set.

big_op_spacing5 
This much vertical space will be added above and below limits.

baseline_sep 
The baselines of the rows in a pile or matrix will normally be
this far apart.
In most cases this should be equal to the sum of
num1 and
denom1. 
shift_down 
The midpoint between the top baseline and the bottom baseline
in a matrix or pile will be shifted down by this much from the axis.
In most cases this should be equal to
axis_height. 
column_sep 
This much space will be added between columns in a matrix.

matrix_side_sep 
This much space will be added at each side of a matrix.

draw_lines 
If this is nonzero, lines will be drawn using the
\D escape sequence, rather than with the
\l escape sequence and the
\(ru character.

body_height 
The amount by which the height of the equation exceeds this
will be added as extra space before the line containing the equation
(using
\x.) The default value is 85.

body_depth 
The amount by which the depth of the equation exceeds this
will be added as extra space after the line containing the equation
(using
\x.) The default value is 35.

nroff 
If this is nonzero,
then
ndefine will behave like
define and
tdefine will be ignored,
otherwise
tdefine will behave like
define and
ndefine will be ignored.
The default value is 0
(This is typically changed to 1 by the
eqnrc file for the
ascii, latin1, utf8, and
cp1047 devices.)
