Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inventions on reducing number of keys on a Computer Keyboard -- A TRIZ
  based analysis   A computer keyboard consists of several sections and each section consists of
several numbers of keys. The text entry section contains the standard character
keys, navigation section contains cursor movement and page control keys,
numeric keypad contains numeric keys and function keys section contain function
keys and special keys. Although the increased number of keys helps smooth
interaction with a computer there are situations where it is necessary to
reduce the number of keys.
  The need for reducing number of keys in a keyboard creates a technical
contradiction. Generally more number of keys can support more number of
functions and less number of keys can support less number of functions. We need
more number of functions (all the functions available in a full size keyboard),
but we want only less number of keys (Contradiction). This contradiction has
been solved by using multi-stroke mechanism.
  There may be different purposes to reduce the number of keys in a keyboard.
Some of them intend to reduce the size of the keyboard while some others intend
to increase the speed of typing. But all of these inventions use multi-stroke
mechanism to generate more number of signals from less number of keys.

14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org