Неопределенные артикли перед прилагательными, которые выделяют какую-либо из характеристик существительного

This map can (may) be extended to all of $X$ in an obvious fashion (way, manner)

A remarkable feature of this solution should be mentioned

Theorem 1 describes in a unified manner the above approach

A simple calculation (computation) yields (gives) $x=y$

Let us consider two random variables with a common distribution

The matrix $A$ has a finite norm not exceeding 1

The function $f$ has a compact support contained in $F$

Now we can rewrite (1) with a new constant $C$

A more general theory follows from this reasoning

This equation has a unique solution for every (each) right-hand side

Однако: this equation has the unique solution $x=1$