What is an anticone in Kaspa's blockDAG?

An anticone is the set of blocks that are neither in the past nor in the future of a given block in Kaspa's blockDAG. In a traditional single-chain blockchain, every block has a strict before-and-after relationship with every other block — nothing exists "alongside" anything else. Kaspa's blockDAG allows multiple blocks to be mined at roughly the same time in different parts of the world, so some blocks end up in a kind of parallel relationship with each other rather than a sequential one. For example, a block mined in Europe might have blocks from North America and Asia in its anticone if those blocks were created concurrently and haven't yet been woven into each other's history. Understanding anticones matters because they are the core reason Kaspa can process many parallel blocks without throwing any of them away — which is what lets it confirm transactions faster than a traditional chain.