The p-adic valuation is a way to measure how many times a particular prime number, called "p," goes into a given integer. Think of it like counting how many apples you have in a basket, but instead of counting each individual apple, you're counting how many times a special apple, called "p," fits inside a bigger apple.
For example, let's say p = 2 and we want to find the p-adic valuation of the number 16. We start by asking ourselves, "How many times does the number 2 go into 16?" Well, it goes in 4 times because 2 x 2 x 2 x 2 = 16. So the p-adic valuation of 16 is 4 because it can be written as 2^4. We can also say that 16 has a "p-adic expansion" of 2^4.
But what if we wanted to find the p-adic valuation of a number that doesn't have p as a factor? For example, let's say p = 3 and we want to find the p-adic valuation of 7. Since 7 doesn't have any factors of 3, we can't write it as a power of 3. In this case, the p-adic valuation of 7 is simply 0 because 3 doesn't go into 7 at all.
Now, you might be wondering why we care about p-adic valuations. One reason is because they can help us understand the properties of certain mathematical objects, like rational numbers or polynomials. Additionally, p-adic numbers (which are like a special type of number that uses p-adic valuations) have some interesting properties, like being able to represent irrational numbers in a unique way.
Overall, the p-adic valuation is a way to measure how many times a special prime number goes into a given integer. It may sound a bit confusing, but it's actually a useful tool for understanding different types of mathematical objects.