mathlib

8d2ffb8f - feat(category_theory): (co)kernels of biproduct projection and inclusion (#12394)

feat(category_theory): (co)kernels of biproduct projection and inclusion (#12394) add kernels and cokernels of biproduct projections and inclusions Co-authored-by: Markus Himmel <markus@himmel-villmar.de> Co-authored-by: Markus Himmel <markus@himmel-villmar.de>