# Fuzzy Logic

Recall the definition of an -ary logic system as a homomorphism with a theory, a structure, and a structure of cardinality such that and have the same signature. **Fuzzy logic** is hereby defined as the study of -ary logic systems where is the cardinality of the continuum. In this sense propositions can be thought of as having valence values in some interval, like So classical binary boolean logic is a type of fuzzy logic, where

**Example 1.** Recall in our construction of a utilitarian set we had a set together with a utility function Now suppose is a set of terms which is also a utilitarian set. Suppose we define a structure on by

This structure has signature Then is also a set of terms, with certain terms in identified, and if is a theory/subset in then is a -ary logic system where has the min and max operations.

In the case of Example 1, if we think of the set of terms as a set of behaviors, which could be construed as terms of persons (acting as words), then the structure can be interpreted as equivalence classes of compound behaviors that yield the same utility where logical valence of compound behaviors is simply based on their utility.

Since the valence set in a fuzzy logic system is an interval, let us look at some common structures on to discuss some intuitive structures on terms. We already mentioned min and max functions and a corresponding structure on class utilitarian sets. is closed under binary multiplication. The corresponding binary connective would thus send two propositions to a proposition whose valence is a product of the original two. Treating binary boolean logic as a fuzzy logic, propositional conjunction satisfies this condition.

**Example 2**. Let be a probability space. Let be closed under addition where any sum exceeding is defined as and define a unary operation by Now note that is closed under union and complementation; denote this structure on by If measurable sets are construed as formulas, select a theory of disjoint sets. Then is a fuzzy logic system.

# Capitalism

**Definition 1.** We define a **static capital system** as a triple with counting measure where and is called the **monetary constant**, is a collection of subsets of such that elements of which are called **owners**, and is called the **worth of ** for an owner

Note we are not requiring to be closed under any operations (i.e. it is not an algebra of sets). Suppose we have two structures on and Let (i.e. a multi-valued map into ). Such a function is called a **trade** (and may correspondingly be thought of as a change of ownership). We define the **trade utility of a trade** as a map by

Again, need not be in but we can of course still define the counting measure on it.

**Definition 2.** A **composite trade** is a map where and are trades.

Note that since it is defined on the image of simply evaluates on all sets in

**Definition 3.** Let be a continuum of static capital systems. We say is a **capital system** if

- for every and there is a unique trade
- (i.e. );
- if and are trades such that then for all

**Example 4.** A capital system is in a **socialist state** at time if for all We may further say is **socialist** during if is in a socialist state for all A capital system is in a **communist state** at time if Similarly we have the definition for **communist** during a set

Note that by this definition a communist state implies a socialist state. In the above regards, a communist state can be thought of as having a single owner (say, “the people”), and socialist state has owners with equal worth.

**Definition 5**. A **dynamic capital system** is a capital system where is a static capital system for all where and are comparable (in the inclusion sense) for all In particular the function defined by is called the **monetary policy**. If is strictly increasing during an interval, we say is **expansionary** during that interval. Similarly it is **contractionary** if it is strictly decreasing on some interval.

**Definition 6.** A dynamic capital system is **rational** if for all

Of course if is we have and thus the condition is satisfied for this case:

So in a rational dynamic capital system we have the inequality

with If exists and is finite, then the rational dynamic capital system is said to have an **end game**.

# A Survey of Utilitarianism

There is a common misconception about the application of the theory of utilitarianism. Many attempt to apply it to events that have happened in history. The purpose of utilitarianism is, really, an attempt to establish a choice function on a set of options. Since events in history presumably happened precisely because of their sets of antecedents, there are no other choices of events; so utilitarian analysis of them is trivial. It can be usefully applied to psychology in the form of decision making. One must decide which behaviors to commit in a given set of circumstances based upon predicted costs and benefits. To approach this rigorously, we will work in ZF theory with special functions.

**Definition 1**. Let be a set and be a function called a **utility function**. The pair will be called a **utilitarian set**. A **sub utilitarian set** is a pair where and .

We will also define the **trivial utilitarian set** as the pair where .

Note that the motivation for closing the codomain on the left is that a behavior bringing death is assumed to be of minimal utility. This allows us to put a choice function on iff (i.e. iff the map is injective). This choice function is defined by

The only problem is that the choice function will pick the “worst” option, and we want to pick the “best”. Let us define

,

.

If is finite and is injective, then for all for some . In this case is a singleton consisting of the “best” element. If is not injective, then we may have . This isn’t a problem for the worst elements; if worst elements all go to the same value, we can just take them all out. But there is also the possibility of having best elements with the same utility.

Define a relation where . This is clearly an equivalence relation. Now consider the set . We have an induced utility function on defined by . By definition of the equivalence relation, we have that any induced utility function on is injective. Hence for any finite , we have a best element of . This is just the set of best elements of .

**Definition 2**. If is a utilitarian set, we call the **class utilitarian set** of .

One can easily see an isomorphism (in the sense that ) between and where and so on. We thus limit ourselves to utilitarian sets where is injective as it always will be on the class set.

Now assume the Axiom of Choice (for purposes of ordering elements of , and note this still doesn’t allow us to pick a “best” element of it trivially, since best is defined by the element taking largest value, if it exists). Let be a utilitarian set with denumerable. Then injectivity of allows for a set to be a bounded strictly monotonically increasing sequence in which in turn contains a convergent subsequence . Note we cannot say the sequence is bounded in the codomain, but it is of course bounded in .

**Definition 3**. Let be a denumerable utilitarian set with injective and an ordering of . We say is a **decidable set** if

where the max is taken over all convergent subseqences of . If is decidable, then the supremum above can be replaced with a maximum (otherwise its value would have been a limit over which the max on the left was taken, and hence, the maximum of them). Hence if is decidable, we define the **best choice** as

.

A utilitarian set is **undecidable** if it is not decidable.

Consider the function defined by

.

This is a semimetric on an arbitrary and a metric when is injective. We can make a modification and define the **opportunity cost of** **with respect to ** by

.

If one assumes that behaviors consume resources proportional to the utility acquired, then the above describes a proportional number of resources lost (or gained if negative) by choosing behavior over .

**Definition 4.** A **discrete path** in is a sequence in , say . A **path** is a continuous map where is endowed with its topology induced by . We can define the **marginal utility of a path** at time and respectively for the type of path by

.

Note the second one may not exist. If one interprets this by defining a sequence for a behavior called “consuming a good” and where represents the number of units of that good consumed, then marginal utility simply represents the change of utility in consuming one additional unit of that good.

If we can accept that all decision making of individuals (i.e. psychology, where biological and environmental factors determine the utility function) models this theory, then aggregately so does that of groups of individuals–making this the foundation of social science.