The statement "All mammals are animals." can be expressed as "If one is mammal then one is an animal." The said first statement is a universal affirmative, and it has been expressed as a conditional statement.
Likewise, the statement "No mammal is an animal.", a universal negative, can be expressed as "If one is a mammal then one is not an animal."
However, I can't seem to find a conditional statement that would be equivalent to particular affirmatives e.g. "Some mammals are animals." or particular negatives e.g. "Some mammals are not animals."
Is there such a conditional statement that could be equivalent to "Some mammals are animals." or "Some mammals are not animals."? What is it? Or, if there is no equivalent conditional statement, how does propositional systems cater to this limitation?