Subadditivity
Okay, so subadditivity is like when you have blocks to build with. Let's say you have some red blocks and some blue blocks.
If you put all of the red blocks and blue blocks together, you can count how many blocks you have in total.
Now let's say you split the blocks up into two piles, one with some of the red blocks and one with some of the blue blocks. You count how many blocks are in each pile, and then you add the two numbers together.
If you did it right, the number you get from adding the two piles should be the same as the number you got when you counted all the blocks together.
That's subadditivity! It means that when you split things into smaller pieces, the total amount shouldn't get bigger. It should stay the same or get smaller.
Like if you have some money, and you split it into two piles to share with your friends, you shouldn't end up with more money than you started with! That wouldn't be fair. So subadditivity is all about fairness and making sure things add up the way they should.
If you put all of the red blocks and blue blocks together, you can count how many blocks you have in total.
Now let's say you split the blocks up into two piles, one with some of the red blocks and one with some of the blue blocks. You count how many blocks are in each pile, and then you add the two numbers together.
If you did it right, the number you get from adding the two piles should be the same as the number you got when you counted all the blocks together.
That's subadditivity! It means that when you split things into smaller pieces, the total amount shouldn't get bigger. It should stay the same or get smaller.
Like if you have some money, and you split it into two piles to share with your friends, you shouldn't end up with more money than you started with! That wouldn't be fair. So subadditivity is all about fairness and making sure things add up the way they should.
Related topics others have asked about: