Challenge

Depending on classification, many no of actions are possible.

$$ 2^n \text{percepts} \rightarrow 2^m \text{actions} $$

Why $2^n$? Given a set of percepts, there would be $2^n$ combinations possible. Each percept is either selected or not, so this results in a binomial theorem situation.

Suppose we have $n=3$ percepts, then there are $2^3$ combinations possible. Each combination's digit is indication if a percept is selected or not.

Let X indicate random variable if a percept is selected(head) or not(tails), so $X = H,T$. Let $n$ indicate no of percepts (at each selection layer, we select one percept or not select). Then the tree could be as below. The digit position could indicate the percept number.

In [3]:
from graphviz import Digraph
from coinflipviz import draw_graph, get_combinations

n_flips = 3  # we have 3 percepts

g = Digraph()
g = draw_graph(g, n_flips)
g

Out[3]:
%3 Root R H1 H Root->H1 p T1 T Root->T1 q H2 H H1->H2 p T2 T H1->T2 q H3 H T1->H3 p T3 T T1->T3 q H4 H H2->H4 p T4 T H2->T4 q H5 H T2->H5 p T5 T T2->T5 q H6 H H3->H6 p T6 T H3->T6 q H7 H T3->H7 p T7 T T3->T7 q
In [4]:
combi_df = get_combinations(n_flips)
combi_df
Out[4]:
sequence x
0 HHH 3
1 THH 2
2 HTH 2
3 TTH 1
4 HHT 2
5 THT 1
6 HTT 1
7 TTT 0

So 8 combinations in each of which, a percept might be selected or not. For eg, $THH$ indicates 1st percept not selected and rest two selected.

Equivalence Classes

Simply convert $2^n$ percepts to $k$ concepts.

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Concept Hierarchies

Often top down..

Establish & Refine

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Imagine in above hierarchy, once we establish Eagle and Bluebird as birds, then a characterisitic like Size could help us differentiate between Eagle and Bluebird, so size could be a new node downwards. In below example, if all are yes in Eager, Bluebird, Penguin, then base class Bird has that charactersitic as Yes.

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May not work all situations

Types of Concepts

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Axiomatic Concepts

Formal set of necessary and sufficient conditions. Easy to program. Easy to communicate.

Eg: Circle; all points in a plane that are equidistant from a single point.

Prototype Concepts

Base concepts defined by typical example with overridable propoerties

Eg: Chair. Note base class has default values, and children overrides some of the notions..

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Exemplar Concepts

Defined by implicit abstractions of instances or exemplars of concept.

Eg: Beauty

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Qulia

Much lesser formal than Exemplar - raw sensation from senses (eg, bitterness)

From values of leaf nodes, predict about the root node..

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