installed immediate method: IsEmpty <=> Dimension( X ) < 0
declared scheme property IsQuasiAffine

(needed for new package AlgebraicThomas)
declared the attribute Closure for (embedded) schemes

(needed for new package AlgebraicThomas)
activated LogicalImplicationsForSchemes

. IsAffine => IsQuasiAffine
. IsEmpty => IsAffine

(needed for new package AlgebraicThomas)
simplified view method for schemes

depends on the activated LogicalImplicationsForSchemes
fixed view method for schemes
view method for empty sheaves now shows the base ring
declared several operations for (embedded) schemes

. Union2 (use it via Union)
. Intersect2 (use it via Intersect)
. Complement
. Difference
. IsSubset

(needed for new package AlgebraicThomas)