[ahmedalsudani]

It's common for the obvious cases and obvious constraints to be assumed.

Adding "distinct" would have made it clearer, but it was obvious that the author meant distinct from reading the title alone.

[someweirdperson]

> Adding "distinct" would have made it clearer, but it was obvious that the author meant distinct from reading the title alone.

It's math. No assumption is ever obvious. Only parts of some proofs are ever allowed to be called obvious.