Visual geometry and the algebraic properties of spinors

Key words of the present paper are visualization and concrete geometry. We develop ordinary two‐component spinor algebra from a concrete geometrical model of spinor space. The null flag picture may be said to constitute such a model as far as topological and differential properties of spinors go. In our model it is also possible to visualize the algebraic properties of spinors by straightforward geometrical constructions. Notably, an interpretation of spinor addition is given in terms of a geometrical procedure, analogous to the addition of real 3‐vectors via the parallelogram rule. By this procedure the relation between the projection of spinors on the 2‐sphere and the projection of their sum can directly be read off. The connection between null flags and our presentation of spinors is touched upon. It is planned to discuss the connection to Minkowski space more closely in a forthcoming paper.