International Mathematical Olympiad selection process Olympiad. Although in principle students of the lower levels may be selected to go to the IMO, it generally takes many years before they can compete with students of the highest level or nivel superior. After the National Competition the twenty best students of each level are invited to the June Training Session where students undergo the IMO selection process. "Hrvatsko matematičko društvo" invites about 20 contestants who performed best at the national level (national level competition is separated by age) to the Croatian Mathematical Olympiad ("Hrvatska matematička olimpijada", HMO) which consists of 2 days, 4 problems each. The best
How many angels can dance on the head of a pin? about how many could perch at the same time on the head of a pin"". Dorothy L. Sayers argued that the question was "simply a debating exercise" and that the answer "usually adjudged correct" was stated as, "Angels are pure intelligences, not material, but limited, so that they have location in space, but not extension." Sayers compares the question to that of how many people's thoughts can be concentrated upon a particular pin at the same time. She concludes that infinitely many angels can be located on the head of a pin, since they do not occupy any space there: