Questions About DAML+OIL Restrictions

Here are some other questions about the DAML+OIL language spec on which
I would like clarification:

Can a restriction have more than one value for property "onProperty?  If
not, is that constraint stated anywhere in the spec?

Can a restriction have values for more than one of the properties
"toClass", "hasClass", "hasValue", "hasClassQ", "minCardinality", ...,
"minCardinalityQ"?  That is, can a single restriction state multiple
constraints?

Is it the case that the following restriction:

(type R Restriction)
(onProperty R P)
(hasClass R C)

is logically equivalent to the following restriction:

(type R1 Restriction)
(onProperty R1 P)
(hasClassQ R1 C)
(minCardinalityQ R1 1)

If so, what is the rationale for having "hasClass" in the language?

Richard