On transparent embeddings of point-line geometries

We introduce the class of transparent embeddings for a point-line geometry Γ=(P,L) as the class of full projective embeddings ε of Γ such that the preimage of any projective line fully contained in ε(P) is a line of Γ. We will then investigate the transparency of Plücker embeddings of projective and polar grassmannians and spin embeddings of half-spin geometries and dual polar spaces of orthogonal type. As an application of our results on transparency, we will derive several Chow-like theorems for polar grassmannians and half-spin geometries.