A projective transformation is a morphism of $P^n$ to $P^n$, for some $n$, determined by an  $(n + 1) \times (n + 1)$ invertible matrix $A$ in the obvious way. The sets $Q$, $R$ are projectively equivalent if and only if there exists a projective transformation $f$ such that $f(Q) = R$.

I would like to know useful criteria to determine if two projective varieties are isomorphic or not.

A projective transformation is a morphism of $P^n$ to $P^n$, for some $n$, determined by an  $(n + 1) \times (n + 1)$ invertible matrix $A$ in the obvious way. The sets $Q$, $R$ are projectively equivalent if and only if there exists a projective transformation $f$ such that $f(Q) = R$.

I would like to know useful criteria to determine if two projective varieties are projectively equivalent.

A projective transformation is a morphism of P^n to P^n, for some n, determined by an (n + 1) x (n + 1) invertible matrix A in the obvious way. The sets Q, R are projectively equivalent if and only if there exists a projective transformation f such that f(Q) = R. I would like to know useful criteria to determine if two projective varieties are isomorphic or not.

A projective transformation is a morphism of $P^n$ to $P^n$, for some $n$, determined by an $(n + 1) \times (n + 1)$ invertible matrix $A$ in the obvious way. The sets $Q$, $R$ are projectively equivalent if and only if there exists a projective transformation $f$ such that $f(Q) = R$.

I would like to know useful criteria to determine if two projective varieties are isomorphic or not.