[matt4711]

In general the techniques in zstd/lzma are much faster than using compressed text indexes.

As a somewhat expert in the field I doubt that this paper has any practical implications.

[faragon]

May be it could be related to a output-code post-processor (e.g. instead of using generic entropy coding postprocessing, compress indexes with an new specific algorithm). If this allows good compression without an additional post-processing step (e.g. avoiding Huffman, arithmetic coding, etc.), it could be very interesting.