Optimal rank-metric codes in Ferrers diagrams are considered. Such codes
consist of matrices having zeros at certain fixed positions and can be used to
construct good codes in the projective space. Four techniques and constructions
of Ferrers diagram rank-metric codes are presented, each providing optimal
codes for different diagrams and parameters.Comment: to be presented in Algebra, Codes, and Networks, Bordeaux, June 16 -
20, 201