Statutory, recognised and upf -- salary income computation

Friends

What is the difference between statutory PF, Recognised PF and Unrecognised PF for computation of income from salary under sections 15 to 17 and consequential tax deduction at source under section 192.

If any company's PF is administered through Trust, it falls under which category.

Is there any clause/rule that a PF trust can deduct TDS on payment of PF dues to an employee who has left the company before 5 years.

Regards,