What mathematical analysis proves that BTC created by 2009 with a fixed supply of 21million.
the math is the block reward in combination with block reward halving.
at the start from first block the reward was 50 bitcoins. then after exactly 210,000 blocks that was automatically cut by half to 25 then after another 210,000 blocks to 12.5 and again to 6.25.
this "halving" will continue until it reaches 0 and that is how the supply cap is enforced.