  In this paper we are interested in a class of fuzzy numbers which is uniquely
identified by their membership functions. The function space, denoted by $X_{h,
p}$, will be constructed by combining a class of nonlinear mappings $h$
(subjective perception) and a class of probability density functions (PDF) $p$
(objective entity), respectively. Under our assumptions, we prove that there
always exists a class of $h$ to fulfill the observed outcome for a given class
of $p$. Especially, we prove that the common triangular number can be
interpreted by a function pair $(h, p)$. As an example, we consider a sample
function space $X_{h, p}$ where $h$ is the tangent function and $p$ is chosen
as the Gaussian kernel with free variable $\mu$. By means of the free variable
$\mu$ (which is also the expectation of $p(x; \mu)$), we define the addition,
scalar multiplication and subtraction on $X_{h, p}$. We claim that, under our
definitions, $X_{h, p}$ has a linear algebra. Some numerical examples are
provided to illustrate the proposed approach.
