PCP is copyrighted program, and licensed under MIT license (also known
as X11 license). This is a very permissive license which allows
anyone, including companies, to use and distribute the source and
binary code of the program, for a fee or for free. The only
requirement is to distribute license notice along with the software.

License notice for PCP can be found in file PCP_LICENSE, and also in
each source file.

In addition to the native code, the program also uses some external
functions and libraries. The libraries and the corresponding licenses
are:

- LIBSVM library by Chih-Chung Chang and Chih-Jen Lin. The license is
  in file LIBSVM_LICENSE. This is a BSD license which is equivalent to
  the MIT license except that the names of authors may not be used to
  promote products using the library. If you distribute PCP or parts
  of PCP which use the library, you must also provide this license
  notice with the distribution.

- hash implementation by Kaz Kylheku. The license is in file
  HASH_LICENSE, and it is even more permissive than the MIT
  license. If you distribute source code for entire PCP or parts of
  PCP which use the HASH library, you must also attach this license.

- PCP contains a C translation of the FORTRAN package CG+ (version
  1.1), written by Guanghui Liu, J. Nocedal and R. Waltz. The CG+
  software is in the public domain, however the authors request that
  the original reference on which the package is based be mentioned in
  all work using CG+. The reference is: J. C. Gilbert and
  J. Nocedal. Global Convergence Properties of Conjugate Gradient
  Methods for Optimization, (1992) SIAM J. on Optimization, 2, 1. In
  other words, if you distribute PCP or parts of PCP which use the
  translated CG+ package, you must also list this reference.

- sorting functions by Ariel Faigon
  (http://www.yendor.com/programming/sort). According to personal
  communication from the author, there are no restrictions on the use
  of the functions.

- LAPACK library. The LAPACK license is contained in file
  LAPACK_LICENSE. The license places minimal restrictions on the
  distribution of the code. The authors of the library request that
  proper credit be given by referencing the LAPACK Users' Guide (you
  should also reference this publication if you distribute PCP or
  parts of PCP which use LAPACK routines):

  Anderson, E., Bai, Z., Bischof, C., Blackford, S., Demmel, J.,
  Dongarra, J., Du Croz, J., Greenbaum, A., Hammarling, S., McKenney,
  A. and Sorensen, D., LAPACK Users' Guide, Third Edition. Society for
  Industrial and Applied Mathematics, Philadelphia, PA, 1999.

In summary, PCP and all its components can be freely used and
distributed in binary and source form, provided that the above notices
are provided with the distribution. All or parts of PCP can be used in
commercial programs as long as the applicable notices accompany the
distribution.