## Quotable Value

Generally the Quotable Value of a
Quotable Deriscope Object as of time t refers to the number that the referenced Quotable attains at that time t under certain modelling and marketing assumptions.

As a demonstration consider the Quotable
Deriscope Type of Stock Price.
An object of type Stock Price contains no actual price data. It describes the referenced stock but does not include the price realized by that stock.
Assuming a unique source of market data feeds, the latter obviously will keep changing with time.
Fixing a time, the stock price quoted in our market data feeds will be then referred as the Quotable Value of our Stock Price object as of that time.

We may even refer to the price that our Stock Price will attain in some future time under certain modelling assumptions.
In that case the price attained in the future ceases to be a simple number and becomes a random variable represented by a probability didtribution as implied by our modelling assumptions.
This means that the Quotable Value of a Quotable object as of a future time t is not a simple number, but rather a random variable.

Both cases above are unified in Deriscope by treating the Quotable Value as an object of type
Probability Measure.
This incorporates the simple number case, since any number can be represented as an object of type
Exact Number.

Since the Quotable Value of a Quotable object represents a random variable that is a function of the observation time t, it follows that the Quotable Value of a Quotable object is evolved according to some stochastic process.