A finite subgroup of the group of units of a commutative field is cyclic.
2.
In general, Pappus's theorem holds for some projective plane if and only if it is a projective plane over a commutative field.
3.
In this section, we consider projective spaces over a commutative field " K ", although most results may be generalized to projective spaces over a division algebra.
4.
Is a finite subgroup of the group of units of a direct product of " n " commutative fields generated by at most " n " elements?
5.
Later studies have indicated that loop-quantum gravity, non-commutative field theories, brane-world scenarios, and random dynamics models also involve the breakdown of Lorentz invariance.
6.
For example, Coxeter's " Projective Geometry ", references Veblen in the three axioms above, together with a further 5 axioms that make the dimension 3 and the coordinate ring a commutative field of characteristic not 2.
7.
Several of the applications above make use of " quasi-Pl & uuml; cker coordinates, " which parametrize noncommutative Grassmannians and flags in much the same way as Pl & uuml; cker coordinates do Grassmannians and flags over commutative fields.