Example 1. Let X = R+,p> 1 a constant and b : X × X → R+ be defined
by
b(x, y) = [max{x, y}]
p + |x − y|
p for all x, y ∈ X.
Then (X, b) is a partial b-metric space with coefficient s = 2p > 1, but
it is neither a b-metric nor a partial metric space. Indeed, for any x > 0