Does a one-to-one function exhibit "injectiveness" or "injectivity"? I'm preparing some tutorials for students and I'm faced with writer's block. If I want to say a function is injective/one-to-one, would the function demonstrate "injectivity" or "injectiveness"? Similarly, what is the convention used for surjective/bijective functions?

Injectivity is derived more in Latin. In French, injectivité is widely used. I wonder how to say "there is an injection from A to B" as easily as in French : "A s'injecte à B".
Invectiveness sounds more Anglo-Saxon, but we rarely see its usage. So we can suppose the employment of such idea is not really English ....
