When we talk about the term 'computationally hard', we usually mean an NP-hard problem. I assume that here, 'memory-hard' means that no other hashing algorithm

When we talk about the term 'computationally hard', we usually mean an NP-hard problem. I assume that here, 'memory-hard' means that no other hashing algorithm can have a greater lower bound on its memory complexity than Scrypt. Is that correct? Edit: After a re-read, I realised that the answer is in the text: "Memory-hard functions (MHFs) are hash algorithms whose evaluation cost is dominated by memory cost."