The kernelkerโก๐ or null space of a linear map๐โ๐ต๐พ๐ผ๐๐(๐,๐) is the the preรฏmage๐โ1{โ๐}, linalg
i.e. the set of all vectors in ๐ that are mapped to โ๐.
It is therefore equivalent to the Kernel of a group homomorphism of ๐ considered as a group homomorphism.
The nullitynullityโก๐ of a linear map is the dimension of its kernel. linalg