  The factorisation scheme (FS) abbreviated as KRK FS including a new
definition of the PDFs for initial hadrons was formulated while developing
KrkNLO scheme of matching QCD NLO corrections for the hard process with the
parton shower heavy boson production in hadron-hadron collision and for deep
inelastic lepton-hadron scattering. KRK FS (originally called Monte Carlo FS)
can be regarded as a variant of the $\overline{MS}$ system. It is therefore
trivially universal, that is process independent. The question of its
universality is formulated differently: As the basic role of KRK FS is to
simplify drastically NLO corrections, the question is now whether the same {\em
single} variant of PDFs in the KRK FS is able to achieve the same maximal
simplification of the NLO corrections for {\em all processes} with one or two
initial hadrons and any number of the final hadrons? Our answer is positive and
the proof is elaborated in the present note within the Catani-Seymour
subtraction methodology. KRK FS is mandatory in the KrkNLO method of matching
NLO calculation and parton shower -- a much simpler alternative of POWHEG
and/or MC\@ NLO. However, the use of KRK FS and the corresponding PDFs
simplifies NLO calculations for any other method of calculating NLO corrections
and for arbitrary processes as well.
