What is the connection between Terminal Total Difficulty (TTD), Difficulty, and Total Difficulty?
Why can Total Difficulty increase if Difficulty decreases?
I know that:
difficulty: QUANTITY - integer of the difficulty for this block.
totalDifficulty: QUANTITY - integer of the total difficulty of the chain until this block.
And I understand what Terminal Total Difficulty (TTD) is in this link
I know that the Hash Rate is proportional to difficulty of the blocks, so if Hash Rate increase then difficulty of the blocks also increase. And because the definition of totalDifficulty is
integer of the total difficulty of the chain until this block.
So it makes me understand that the more difficulty, the more total difficulty. And therefore, when total difficulty increases, it will reach the TTD, and that time The Merge will be successful.
Can anybody help me to understand why the Difficulty (and hash rate) is decreasing, while Total Difficulty is increasing to reach the TTD? I think the Difficulty (and hash rate) need to be increasing for the increase of Total Difficulty because of its definition: Total Difficulty is integer of the total difficulty of the chain until this block.