reserve i, i1, i2, j, j1, j2, k, m, n, t for Nat,
  D for non empty Subset of TOP-REAL 2,
  E for compact non vertical non horizontal Subset of TOP-REAL 2,
  C for compact connected non vertical non horizontal Subset of TOP-REAL 2,
  G for Go-board,
  p, q, x for Point of TOP-REAL 2,
  r, s for Real;

theorem Th25:
  i<=len G & j<=width G implies cell(G,i,j) is connected
proof
  assume
A1: i<=len G & j<=width G;
  then Int cell(G,i,j) is convex by GOBOARD9:17;
  then Cl Int cell(G,i,j) is connected by CONNSP_1:19;
  hence thesis by A1,GOBRD11:35;
end;
