Harts per core on U54?

Might be a dumb question, but I’m going through the U54 manual and there’s no explicit statement about whether the five harts correspond to the five cores (1 S51 and 4 U54). All I can find is this google groups thread:

https://groups.google.com/a/groups.riscv.org/forum/#!topic/sw-dev/QKjUDjz_vKo

Which does say that each core is single-threaded, but I’d like a second opinion to make sure. Thanks!

The response from Palmer in that thread should be considered definitive. He is one of the experts on this.
https://groups.google.com/a/groups.riscv.org/d/msg/sw-dev/QKjUDjz_vKo/xAV6BWfsBwAJ