[mizar] New Mizar articles

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

Christoph Schwarzweller submitted an article entitled:
      "Characterization and Existence of Gr\"obner Bases"
        (MML identifier: GROEB_1)

Christoph Schwarzweller submitted an article entitled:
      "Construction of Gr\"obner bases. S-Polynomials and
   Standard Representations"
        (MML identifier: GROEB_2)

Adam Grabowski submitted an article entitled:
      "On the Subcontinua of a Real Line"
        (MML identifier: BORSUK_5)

Lilla Krystyna Baginska and Adam Grabowski submitted an article entitled:
      "On the Kuratowski Closure-Complement Problem"
        (MML identifier: KURATO_1)

Noboru Endou and Yasunari Shidama submitted an article entitled:
      "Convex Hull, Set of Convex Combinations and Convex Cone"
        (MML identifier: CONVEX3)

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