[mizar] New Mizar articles

[Adam Grabowski <adam@math.uwb.edu.pl>]

Masaaki Niimura and Yasushi Fuwa submitted articles entitled:
      "Improvement of Radix-$2^k$ Signed-Digit Number for High Speed Circuit"
        (MML identifier: RADIX_3)
      "High Speed Adder Algorithm with Radix-$2^k$ SD\_Sub Number"
        (MML identifier: RADIX_4)

to the Mizar Mathematical Library.  The preprints of the articles are
available at:

 http://mizar.uwb.edu.pl/JFM/Preprints.html

-----
  Library Committee of the Association of Mizar Users