Class

Time Space PR

FT Space PR

I

II

mathematically OK,

but step function physically

unachievable

III

alternate equivalent definition (67) - (74):

see Eqs. (36) for lack of proper

equivalent physical relation in space

IV

V

VI

for only, all other

same physical restriction as Class II

for or

plus must be time independent over

the entire time interval

VII

this Class should be the PR of choice as it

is path independent and hence

universal