American Meteorological Society (Jack Gittinger)
... 3. Give an example of a function that is neither one-to-one nor onto 4. Give an example of a function that is both one-to-one and onto 5. How many functions are there from A = {1,2} to B = {a, b}? Write them as sets of ordered pairs. Which are one-to-one? Which are onto? 6. Let X = {1, 2, 3, 4}, Y = ...
... 3. Give an example of a function that is neither one-to-one nor onto 4. Give an example of a function that is both one-to-one and onto 5. How many functions are there from A = {1,2} to B = {a, b}? Write them as sets of ordered pairs. Which are one-to-one? Which are onto? 6. Let X = {1, 2, 3, 4}, Y = ...
Surprising Connections between Partitions and Divisors
... constructed as a product of prime numbers. One object of concern here is the “sum of divisors function” σ (n), which is just that, the sum of the divisors of n. For example, the divisors of the number 6 are 1, 2, 3, and 6, and thus σ (6) = 12. Clearly, prime numbers are associated with this function ...
... constructed as a product of prime numbers. One object of concern here is the “sum of divisors function” σ (n), which is just that, the sum of the divisors of n. For example, the divisors of the number 6 are 1, 2, 3, and 6, and thus σ (6) = 12. Clearly, prime numbers are associated with this function ...
