| A)   | 
The computer provides for precise and general conversation.
   | 
| B)   | 
Texts such as 
Fractals, Visualization and J [7], 
Exploring Math [8], and 
Concrete Math Companion [14] 
use the language in a variety of topics.
   | 
| C)   | 
The appended dictionary of J provides a complete 
and concise dictionary and grammar.
   | 
| D)   | 
J Phrases [9] provides guidance 
in writing programs, and almost any topic provides problems of 
a wide range of difficulty.
   | 
| E)   | 
Words possess considerable structure, as in +: 
and -: and *: and %: for double,
 halve, square, and square root.  
Moreover, a beginner can assign and use mnemonic names appropriate 
to any native language, as in sqrt=:%: and entier=:<. 
(French name) and sin=:1&o. and SIN=:1&o.@(%&180@o.) 
(for sine in degrees).
   | 
We will hereafter introduce and use new primitives with 
little or no discussion, assuming that the reader will 
experiment with them on the computer, consult the dictionary 
to determine their meanings, or perhaps infer their meanings 
from their structure. For example, the appearance of the 
word