### 3 Typographic Conventions

Technical terms are shown in a bold font like this the first time that they are used. Also:

Anything that is to be typed into a computer program via the keyboard,
or output from one via the screen, is indicated by a ‘typewriter’ or
‘courier’ font like this.

However:

items appearing in graphical windows, such as those used by GAIA or xreduce, are shown in a sans serif font like this.