Affine projections
Using the Moore-Penrose pseudoinverse of a matrix (a reference is \textit{C. D. Meyer}'s book [Matrix analysis and applied linear algebra (2000; Zbl 0962.15001)]), the authors construct projections of a vector on affine subspaces of a vector space. Some formulas for projecting onto intersections and sums of subspaces are also given. Some comparison formulas with the vectorial projections are considered. There are also a lot of examples illustrating the theory.
scientific article; zbMATH DE number 2142455