COPYING.FDL

                     GNU FREE DOCUMENTATION LICENSE
                      Version 1.3, 3 November 2008

Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation,
Inc. <https://fsf.org/>. Everyone is permitted to copy and distribute
verbatim copies of this license document, but changing it is not allowed.

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 works of
the document must themselves be free in the same sense. It 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 software
does. But this License is not limited to software manuals; it can be used
for any textual work, regardless of subject matter or whether it is
published as a printed book. We recommend this License 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
distributed under the terms of this License. Such a notice grants a
world-wide, royalty-free license, unlimited in duration, to use that work
under the conditions stated herein. The "Document", below, refers to any
such manual or work. Any member of the public is a licensee, and is
addressed as "you". You accept the license if you 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 within that overall
subject. (Thus, if the Document is in part a textbook of mathematics, a
Secondary Section may not explain any mathematics.) The relationship could
be a matter of historical 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 that says
that the Document is released under this License. If a section does not fit
the above definition of Secondary then it is not allowed to be designated
as Invariant. The Document may contain zero Invariant Sections. If the
Document does not identify any Invariant 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 the
Document is released under this License. A Front-Cover Text may 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 to text formatters. A copy made in an
otherwise Transparent file 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 of text. A copy that is not "Transparent" is called
"Opaque".

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 HTML, PostScript
or PDF designed for human modification. Examples of transparent image
formats include PNG, XCF and JPG. Opaque formats 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 this
License requires to appear in the title page. For works in 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.

The "publisher" means any person or entity that distributes copies of the
Document to the public.

A section "Entitled XYZ" means a named subunit of the Document whose title
either is precisely XYZ or contains XYZ in parentheses following text that
translates XYZ in another language. (Here XYZ stands for a specific section
name mentioned below, such as "Acknowledgements", "Dedications",
"Endorsements", or "History".) To "Preserve the Title" 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
states that this License applies to the Document. These Warranty
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 conditions whatsoever
to those of this License. You may not use technical measures to obstruct or
control the reading or further copying of the copies you make or
distribute. However, you may accept compensation in exchange for copies. If
you distribute a large enough 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 back
cover. Both covers must also clearly and legibly identify you as the
publisher of these copies. The front cover must present the full title with
all words of the title equally prominent and visible. You may add other
material on the covers in addition. Copying with changes limited to the
covers, as long as they preserve the title of the Document and satisfy
these conditions, can be treated as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit legibly,
you should put the first ones listed (as many as fit reasonably) on the
actual cover, and continue the rest onto adjacent pages.

If you publish or distribute Opaque copies of the Document numbering more
than 100, you must either include a machine-readable Transparent copy along
with each Opaque copy, or state in or with each Opaque copy a
computer-network location from which the general network-using public has
access to download using public-standard network protocols a complete
Transparent copy of the Document, free of added material. If you use the
latter option, you must take reasonably prudent steps, when you begin
distribution of Opaque copies in quantity, to ensure that this Transparent
copy will remain thus accessible at the stated location until at least one
year after the last time you distribute an Opaque copy (directly or through
your agents or retailers) of that edition to the public.

It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to give
them a chance to provide you with an updated version of the Document.

4. MODIFICATIONS

You may copy and distribute a Modified Version of the Document under the
conditions of sections 2 and 3 above, provided that you release the
Modified Version under precisely this License, with the Modified Version
filling the role of the Document, thus licensing distribution and
modification of the Modified Version to whoever possesses a copy of it. In
addition, you must do these things in the Modified Version:
    A. Use in the Title Page (and on the covers, if any) a title distinct
       from that of the Document, and from those of previous versions
       (which should, if there were any, be listed in the History section
       of the Document). You may use the same title as a previous version
       if the original publisher of that version gives permission.
    B. List on the Title Page, as authors, one or more persons or entities
       responsible for authorship of the modifications in the Modified
       Version, together with at least five of the principal authors of the
       Document (all of its principal authors, if it has fewer than five),
       unless they release you from this requirement.
    C. State on the Title page the name of the publisher of the Modified
       Version, as the publisher.
    D. Preserve all the copyright notices of the Document.
    E. Add an appropriate copyright notice for your modifications adjacent
       to the other copyright notices.
    F. Include, immediately after the copyright notices, a license notice
       giving the public permission to use the Modified Version under the
       terms of this License, in the form shown in the Addendum below.
    G. Preserve in that license notice the full lists of Invariant Sections
       and required Cover Texts given in the Document's license notice.
    H. Include an unaltered copy of this License.
    I. Preserve the section Entitled "History", Preserve its Title, and add
       to it an item stating at least the title, year, new authors, and
       publisher of the Modified Version as given on the Title Page. If
       there is no section Entitled "History" in the Document, create one
       stating the title, year, authors, and publisher of the Document as
       given on its Title Page, then add an item describing the Modified
       Version as stated in the previous sentence.
    J. Preserve the network location, if any, given in the Document for
       public access to a Transparent copy of the Document, and likewise
       the network locations given in the Document for previous versions it
       was based on. These may be placed in the "History" section. You may
       omit a network location for a work that was published at least four
       years before the Document itself, or if the original publisher of
       the version it refers to gives permission.
    K. For any section Entitled "Acknowledgements" or "Dedications",
       Preserve the Title of the section, and preserve in the section all
       the substance and tone of each of the contributor acknowledgements
       and/or dedications given therein.
    L. Preserve all the Invariant Sections of the Document, unaltered in
       their text and in their titles. Section numbers or the equivalent
       are not considered part of the section titles.
    M. Delete any section Entitled "Endorsements". Such a section may not
       be included in the Modified Version.
    N. Do not retitle any existing section to be Entitled "Endorsements" or
       to conflict in title with any Invariant Section.
    O. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections or appendices
that qualify as Secondary Sections and contain no material copied from the
Document, you may at your option designate some or all of these sections as
invariant. To do this, add their titles to the list of Invariant Sections
in the Modified Version's license notice. These titles must be distinct
from any other section titles.

You may add a section Entitled "Endorsements", provided it contains nothing
but endorsements of your Modified Version by various parties—for example,
statements of peer review or that the text has been approved by an
organization as the authoritative definition of a standard.

You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list of
Cover Texts in the Modified Version. Only one passage of Front-Cover Text
and one of Back-Cover Text may be added by (or through arrangements made
by) any one entity. If the Document already includes a cover text for the
same cover, previously added by you or by arrangement made by the same
entity you are acting on behalf of, you may not add another; but you may
replace the old one, on explicit permission from the previous publisher
that added the old one.

The author(s) and publisher(s) of the Document do not by this License give
permission to use their names for publicity for or to assert or imply
endorsement of any Modified Version.

5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified versions,
provided that you include in the combination all of the Invariant Sections
of all of the original documents, unmodified, and list them all as
Invariant Sections of your combined work in its license notice, and that
you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and multiple
identical Invariant Sections may be replaced with a single copy. If there
are multiple Invariant Sections with the same name but different contents,
make the title of each such section unique by adding at the end of it, in
parentheses, the name of the original author or publisher of that section
if known, or else a unique number. Make the same adjustment to the section
titles in the list of Invariant Sections in the license notice of the
combined work.

In the combination, you must combine any sections Entitled "History" in the
various original documents, forming one section Entitled "History";
likewise combine any sections Entitled "Acknowledgements", and any sections
Entitled "Dedications". You must delete all sections Entitled
"Endorsements".

6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in the
collection, provided that you follow the rules of this License for verbatim
copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute it
individually under this License, provided you insert a copy of this License
into the extracted document, and follow this License in all other respects
regarding verbatim copying of that document.

7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate and
independent documents or works, in or on a volume of a storage or
distribution medium, is called an "aggregate" if the copyright resulting
from the compilation is not used to limit the legal rights of the
compilation's users beyond what the individual works permit. When the
Document is included in an aggregate, this License does not apply to the
other works in the aggregate which are not themselves derivative works of
the Document.

If the Cover Text requirement of section 3 is applicable to these copies of
the Document, then if the Document is less than one half of the entire
aggregate, the Document's Cover Texts may be placed on covers that bracket
the Document within the aggregate, or the electronic equivalent of covers
if the Document is in electronic form. Otherwise they must appear on
printed covers that bracket the whole aggregate.

8. TRANSLATION

Translation is considered a kind of modification, so you may distribute
translations of the Document under the terms of section 4. Replacing
Invariant Sections with translations requires special permission from their
copyright holders, but you may include translations of some or all
Invariant Sections in addition to the original versions of these Invariant
Sections. You may include a translation of this License, and all the
license notices in the Document, and any Warranty Disclaimers, provided
that you also include the original English version of this License and the
original versions of those notices and disclaimers. In case of a
disagreement between the translation and the original version of this
License or a notice or disclaimer, the original version will prevail.

If a section in the Document is Entitled "Acknowledgements", "Dedications",
or "History", the requirement (section 4) to Preserve its Title (section 1)
will typically require changing the actual title.

9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document except as
expressly provided under this License. Any attempt otherwise to copy,
modify, sublicense, or distribute it is void, and will automatically
terminate your rights under this License.

However, if you cease all violation of this License, then your license from
a particular copyright holder is reinstated (a) provisionally, unless and
until the copyright holder explicitly and finally terminates your license,
and (b) permanently, if the copyright holder fails to notify you of the
violation by some reasonable means prior to 60 days after the cessation.

Moreover, your license from a particular copyright holder is reinstated
permanently if the copyright holder notifies you of the violation by some
reasonable means, this is the first time you have received notice of
violation of this License (for any work) from that copyright holder, and
you cure the violation prior to 30 days after your receipt of the notice.

Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under this
License. If your rights have been terminated and not permanently
reinstated, receipt of a copy of some or all of the same material does not
give you any rights to use it.

10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the GNU
Free Documentation License from time to time. Such new versions will be
similar in spirit to the present version, but may differ in detail to
address new problems or concerns. See https://www.gnu.org/licenses/.

Each version of the License is given a distinguishing version number. If
the Document specifies that a particular numbered version of this License
"or any later version" applies to it, you have the option of following the
terms and conditions either of that specified version or of any later
version that has been published (not as a draft) by the Free Software
Foundation. If the Document does not specify a version number of this
License, you may choose any version ever published (not as a draft) by the
Free Software Foundation. If the Document specifies that a proxy can decide
which future versions of this License can be used, that proxy's public
statement of acceptance of a version permanently authorizes you to choose
that version for the Document.

11. RELICENSING

"Massive Multiauthor Collaboration Site" (or "MMC Site") means any World
Wide Web server that publishes copyrightable works and also provides
prominent facilities for anybody to edit those works. A public wiki that
anybody can edit is an example of such a server. A "Massive Multiauthor
Collaboration" (or "MMC") contained in the site means any set of
copyrightable works thus published on the MMC site.

"CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0 license
published by Creative Commons Corporation, a not-for-profit corporation
with a principal place of business in San Francisco, California, as well as
future copyleft versions of that license published by that same
organization.

"Incorporate" means to publish or republish a Document, in whole or in
part, as part of another Document.

An MMC is "eligible for relicensing" if it is licensed under this License,
and if all works that were first published under this License somewhere
other than this MMC, and subsequently incorporated in whole or in part into
the MMC, (1) had no cover texts or invariant sections, and (2) were thus
incorporated prior to November 1, 2008.

The operator of an MMC Site may republish an MMC contained in the site
under CC-BY-SA on the same site at any time before August 1, 2009, provided
the MMC is eligible for relicensing.

ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of the
License in the document and put the following copyright and license notices
just after the title page:

    Copyright (C)  YEAR  YOUR NAME.
    Permission is granted to copy, distribute and/or modify this document
    under the terms of the GNU Free Documentation License, Version 1.3
    or any later version published by the Free Software Foundation;
    with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
    A copy of the license is included in the section entitled "GNU
    Free Documentation License".

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the "with … Texts." line with this:

    with the Invariant Sections being LIST THEIR TITLES, with the
    Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.

If your document contains nontrivial examples of program code, we recommend
releasing these examples in parallel under your choice of free software
license, such as the GNU General Public License, to permit their use in
free software.