Отсутствие артиклей перед существительными, используемых после to have без последующего уточнения этого существительного

The (a) matrix $A$ has finite norm (но has a finite norm not exceeding $n$)

This function has compact support (но has a compact support contained in $R$)

This matrix has rank $n$

$F$ has cardinality $c$

This variable has absolute value 1

This matrix has determinant zero

It is assumed that the matrix $A$ has full rank

This function has zero (но has a zero of order at least $n$ at the origin of coordinates)

This distribution has density $g$ (если символ $g$ упоминался ранее; если нет, то has a density $g$)

The number associated with a point on the plane has geometric significance