License is intended to guarantee your freedom to share and change free

General Public License applies to most of the Free Software

Foundation's software and to any other program whose authors commit to

your programs, too.

have the freedom to distribute copies of free software (and charge for

this service if you wish), that you receive source code or can get it

if you want it, that you can change the software or use pieces of it

in new free programs; and that you know you can do these things.

anyone to deny you these rights or to ask you to surrender the rights.

These restrictions translate to certain responsibilities for you if you

distribute copies of the software, or if you modify it.

gratis or for a fee, you must give the recipients all the rights that

rights.

(2) offer you this license which gives you legal permission to copy,

distribute and/or modify the software.

that everyone understands that there is no warranty for this free

want its recipients to know that what they have is not the original, so

that any problems introduced by others will not reflect on the original

authors' reputations.

program will individually obtain patent licenses, in effect making the

patent must be licensed for everyone's free use or not licensed at all.

modification follow.

a notice placed by the copyright holder saying it may be distributed

refers to any such program or work, and a "work based on the Program"

means either the Program or any derivative work under copyright law:

that is to say, a work containing the Program or a portion of it,

either verbatim or with modifications and/or translated into another

Activities other than copying, distribution and modification are not

running the Program is not restricted, and the output from the Program

is covered only if its contents constitute a work based on the

Program (independent of having been made by running the Program).

Whether that is true depends on what the Program does.

source code as you receive it, in any medium, provided that you

conspicuously and appropriately publish on each copy an appropriate

copyright notice and disclaimer of warranty; keep intact all the

notices that refer to this License and to the absence of any warranty;

and give any other recipients of the Program a copy of this License

along with the Program.

You may charge a fee for the physical act of transferring a copy, and

you may at your option offer warranty protection in exchange for a fee.

of it, thus forming a work based on the Program, and copy and

distribute such modifications or work under the terms of Section 1

above, provided that you also meet all of these conditions:

identifiable sections of that work are not derived from the Program,

and can be reasonably considered independent and separate works in

themselves, then this License, and its terms, do not apply to those

distribute the same sections as part of a whole which is a work based

on the Program, the distribution of the whole must be on the terms of

this License, whose permissions for other licensees extend to the

entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest

your rights to work written entirely by you; rather, the intent is to

exercise the right to control the distribution of derivative or

collective works based on the Program.

In addition, mere aggregation of another work not based on the Program

with the Program (or with a work based on the Program) on a volume of

a storage or distribution medium does not bring the other work under

the scope of this License.

under Section 2) in object code or executable form under the terms of

Sections 1 and 2 above provided that you also do one of the following:

The source code for a work means the preferred form of the work for

code means all the source code for all modules it contains, plus any

associated interface definition files, plus the scripts used to

special exception, the source code distributed need not include

anything that is normally distributed (in either source or binary

form) with the major components (compiler, kernel, and so on) of the

operating system on which the executable runs, unless that component

itself accompanies the executable.

If distribution of executable or object code is made by offering

access to copy from a designated place, then offering equivalent

access to copy the source code from the same place counts as

distribution of the source code, even though third parties are not

compelled to copy the source along with the object code.

otherwise to copy, modify, sublicense or distribute the Program is

void, and will automatically terminate your rights under this License.

However, parties who have received copies, or rights, from you under

this License will not have their licenses terminated so long as such

parties remain in full compliance.

modifying or distributing the Program (or any work based on the

Program), you indicate your acceptance of this License to do so, and

all its terms and conditions for copying, distributing or modifying

the Program or works based on it.

Program), the recipient automatically receives a license from the

original licensor to copy, distribute or modify the Program subject to

restrictions on the recipients' exercise of the rights granted herein.

You are not responsible for enforcing compliance by third parties to

this License.

infringement or for any other reason (not limited to patent issues),

conditions are imposed on you (whether by court order, agreement or

otherwise) that contradict the conditions of this License, they do not

distribute so as to satisfy simultaneously your obligations under this

License and any other pertinent obligations, then as a consequence you

license would not permit royalty-free redistribution of the Program by

all those who receive copies directly or indirectly through you, then

the only way you could satisfy both it and this License would be to

refrain entirely from distribution of the Program.

If any portion of this section is held invalid or unenforceable under

any particular circumstance, the balance of the section is intended to

apply and the section as a whole is intended to apply in other

circumstances.

It is not the purpose of this section to induce you to infringe any

patents or other property right claims or to contest validity of any

such claims; this section has the sole purpose of protecting the

integrity of the free software distribution system, which is

generous contributions to the wide range of software distributed

through that system in reliance on consistent application of that

system; it is up to the author/donor to decide if he or she is willing

to distribute software through any other system and a licensee cannot

impose that choice.

This section is intended to make thoroughly clear what is believed to

be a consequence of the rest of this License.

certain countries either by patents or by copyrighted interfaces, the

original copyright holder who places the Program under this License

may add an explicit geographical distribution limitation excluding

those countries, so that distribution is permitted only in or among

the limitation as if written in the body of this License.

be similar in spirit to the present version, but may differ in detail to

address new problems or concerns.

specifies a version number of this License which applies to it and "any

later version", you have the option of following the terms and conditions

either of that version or of any later version published by the Free

this License, you may choose any version ever published by the Free Software

Foundation.

programs whose distribution conditions are different, write to the author

Software Foundation, write to the Free Software Foundation; we sometimes

of preserving the free status of all derivatives of our free software and

of promoting the sharing and reuse of software generally.

OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES

PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED

OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,

REPAIR OR CORRECTION.

WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR

REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,

INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING

OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED

TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY

YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER

PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE

POSSIBILITY OF SUCH DAMAGES.

possible use to the public, the best way to achieve this is to make it

free software which everyone can redistribute and change under these terms.

to attach them to the start of each source file to most effectively

convey the exclusion of warranty; and each file should have at least

the "copyright" line and a pointer to where the full notice is found.

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this

when it starts in an interactive mode:

The hypothetical commands `show w' and `show c' should show the appropriate

be called something other than `show w' and `show c'; they could even be

mouse-clicks or menu items--whatever suits your program.

You should also get your employer (if you work as a programmer) or your

school, if any, to sign a "copyright disclaimer" for the program, if

This General Public License does not permit incorporating your program into

consider it more useful to permit linking proprietary applications with the

Public License instead of this License.

0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other

functional and useful document "free" in the sense of freedom: to

assure everyone the effective freedom to copy and redistribute it,

with or without modifying it, either commercially or noncommercially.

Secondarily, this License preserves for the author and publisher a way

to get credit for their work, while not being considered responsible

for modifications made by others.

This License is a kind of "copyleft", which means that derivative

complements the GNU General Public License, which is a copyleft

license designed for free software.

We have designed this License in order to use it for manuals for free

software, because free software needs free documentation: a free

program should come with manuals providing the same freedoms that the

it can be used for any textual work, regardless of subject matter or

principally for works whose purpose is instruction or reference.

1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that

contains a notice placed by the copyright holder saying it can be

world-wide, royalty-free license, unlimited in duration, to use that

copy, modify or distribute the work in a way requiring permission

under copyright law.

A "Modified Version" of the Document means any work containing the

Document or a portion of it, either copied verbatim, or with

modifications and/or translated into another language.

A "Secondary Section" is a named appendix or a front-matter section of

the Document that deals exclusively with the relationship of the

publishers or authors of the Document to the Document's overall subject

(or to related matters) and contains nothing that could fall directly

textbook of mathematics, a Secondary Section may not explain any

connection with the subject or with related matters, or of legal,

commercial, philosophical, ethical or political position regarding

them.

The "Invariant Sections" are certain Secondary Sections whose titles

are designated, as being those of Invariant Sections, in the notice

section does not fit the above definition of Secondary then it is not

Sections then there are none.

The "Cover Texts" are certain short passages of text that are listed,

as Front-Cover Texts or Back-Cover Texts, in the notice that says that

be at most 5 words, and a Back-Cover Text may be at most 25 words.

A "Transparent" copy of the Document means a machine-readable copy,

represented in a format whose specification is available to the

general public, that is suitable for revising the document

straightforwardly with generic text editors or (for images composed of

pixels) generic paint programs or (for drawings) some widely available

drawing editor, and that is suitable for input to text formatters or

for automatic translation to a variety of formats suitable for input

format whose markup, or absence of markup, has been arranged to thwart

or discourage subsequent modification by readers is not Transparent.

An image format is not Transparent if used for any substantial amount

Examples of suitable formats for Transparent copies include plain

ASCII without markup, Texinfo input format, LaTeX input format, SGML

or XML using a publicly available DTD, and standard-conforming simple

include proprietary formats that can be read and edited only by

proprietary word processors, SGML or XML for which the DTD and/or

processing tools are not generally available, and the

machine-generated HTML, PostScript or PDF produced by some word

processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself,

plus such following pages as are needed to hold, legibly, the material

formats which do not have any title page as such, "Title Page" means

the text near the most prominent appearance of the work's title,

preceding the beginning of the body of the text.

A section "Entitled XYZ" means a named subunit of the Document whose

title either is precisely XYZ or contains XYZ in parentheses following

specific section name mentioned below, such as "Acknowledgements",

of such a section when you modify the Document means that it remains a

section "Entitled XYZ" according to this definition.

The Document may include Warranty Disclaimers next to the notice which

Disclaimers are considered to be included by reference in this

License, but only as regards disclaiming warranties: any other

implication that these Warranty Disclaimers may have is void and has

no effect on the meaning of this License.

2. VERBATIM COPYING

You may copy and distribute the Document in any medium, either

commercially or noncommercially, provided that this License, the

copyright notices, and the license notice saying this License applies

to the Document are reproduced in all copies, and that you add no other

technical measures to obstruct or control the reading or further

number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and

you may publicly display copies.

3. COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonly have

printed covers) of the Document, numbering more than 100, and the

Document's license notice requires Cover Texts, you must enclose the

copies in covers that carry, clearly and legibly, all these Cover

Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on

the full title with all words of the title equally prominent and

Copying with changes limited to the covers, as long as they preserve