The index level increases inside certain mathematical constructs such as indices and fractions. When the index level is high, formulas are rendered in a smaller font. Nevertheless, index levels higher than 2 are all rendered in the same way as index level 2; this ensures that formulas like

ⅇ ^ⅇⅇⅇx =

1 + 1 x + ⅇx

1 + 1 ⅇx + 1 ⅇⅇx

remain readable. The index level may be manually changed in Format→Index level, so as to produce formulas like

x^yz

This environement variable controls whether we are in display style or not. Formulas which occur on separate lines like

n

H(α1,…,αn)

=

1

α1

+ ⋯ +

1

αn

are usually typeset in display style, contrary to inline formulas like

n

H(α1,…,αn)

=

1

α1

+ ⋯ +

1

αn

. As you notice, formulas in display style are rendered using a wider spacing. The display style is disabled in several mathematical constructs such as scripts, fractions, binomial coefficients, and so on. As a result, the double numerators in the formula

H (α ₁ ,…,α _n ) =

n

1 α1 + ⋯ + 1 αn

are typeset in a smaller font. You may override the default settings using Format→Display style.

By default, formulas like a + ⋯ + z are typeset using a nice, wide spacing around the + symbol. In formulas with scripts like ⅇ^{a + ⋯ + z} + ⅇ^{α + ⋯ + ζ} the readability is further enhanced by using a more condensed spacing inside the scripts: this helps the reader to distinguish symbols occurring in the scripts from symbols occurring at the ground level when the scripts are long. The default behaviour can be overridden using Format→Condensed.

For a high quality typesetting of fraction, it is good to avoid subscripts in numerators to descend to low and superscripts in denominators to ascend to high. TeXmacs therefore provides an additional environment variable math-vpos which takes the value 1 inside numerators, −1 inside denominators and 0 otherwise. In order to see the effect the different settings, consider the following formula:

a

2

−1

+ a

2

0

+ a

2

1

In this example, the grouping is necessary in order to let the different vertical positions take effect on each a

2

i

. Indeed, the vertical position is uniform for each horizontal concatenation.