HTLCs use a hash of a preimage as the lock and the preimage as the key and PTLCs use a public key (point) as the lock and a signature from that public key as the key, see https://bitcoinops.org/en/topics/ptlc/
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What sort of benefits will using one or the other have?
edit Nvm its literally in the link
Compared to HTLCs, they can be more private and use less block space.
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