General :: Difference Between Child THREAD And Child PROCESS?

I am troubleshooting something and I got this problem.

If I do "pstree -p"

It shows,

Code:

[code]....

However, it does NOT show up in "ps -elf"

Code:

ps -elf | grep soffi
0 S whho 7734 1 0 80 0 - 36435 - 11:14 pts/2 00:00:03 /usr/lib/openoffice/program/soffice.bin -splash-pipe=5
0 S whho 7833 7759 0 80 0 - 751 - 11:21 pts/3 00:00:00 grep soffi

I was wondering if 7735, 7736, 7737, 7743 were really processes. Then I checked /proc, I could cd to /proc/7735, /proc/7736, etc, but I could not ls them out. I looked at the man page of "pstree", it says,

Code:

Child threads of a process are found under the parent process and are shown with the process name in curly braces, e.g.

icecast2---13*[{icecast2}]

So, what does all this mean? Does it mean that 7735, 7736, 7737, 7743 are just threads but not processes? If so, why could I cd to /proc/<id> but not see them in "ps -elf".