  The real world is inherently uncertain, imprecise and vague. Soft set theory
was firstly introduced by Molodtsov in 1999 as a general mathematical tool for
dealing with uncertainties, not clearly defined objects. A soft set consists of
two parts which are parameter set and approximate value set. So while talking
about any property on a soft set, it is notable to consider that each parts
should be evaluated separately. In this paper, by taking into account this
case, we firstly define the concept of cardinality of soft hybrid sets which
are soft set, fuzzy soft set, fuzzy parameterized soft set and fuzzy
parameterized fuzzy soft set. Then we discuss the entropy, similarity and
subsethood measures based on cardinality in a soft hybrid set, and investigate
the relationships among these concepts as well as related examples. Finally, we
present an application which is a representation method based on cardinality of
a soft hybrid space.
