noun
nullity
In linear algebra, the dimension of the null space (kernel) of a linear transformation or matrix; the number of linearly independent solutions to the homogeneous equation.
行列の退化次数は、その階数と列の数から計算できる。
The nullity of a matrix can be calculated from its rank and the number of columns.
退化次数がゼロでない場合、その線形写像は単射ではない。
If the nullity is not zero, the linear transformation is not injective.
Compound of 退化 (degeneration, retrogression) and 次数 (degree, number of times). The term is a direct translation of the mathematical concept 'nullity'.