Beschreibung:
<jats:p>In this paper, we give the generic classification of the singularities of 3-parameter line congruences in <jats:inline-formula><jats:alternatives><jats:tex-math>$\mathbb {R}^{4}$</jats:tex-math><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S0308210522000415_inline2.png" /></jats:alternatives></jats:inline-formula>. We also classify the generic singularities of normal and Blaschke (affine) normal congruences.</jats:p>