Question

Display the table produced by applying the projection \({P_{1,2,4}}\) to Table 8.

Short answer

The resultant answer is explained.

Step-by-step solution

Given data

Table 8 is given.

Concept of sets

The concept of set is a very basic one.

It is simple; yet, it suffices as the basis on which all abstract notions in mathematics can be built.\(A\)set is determined by its elements.

If\(A\)is a set, write\(x \in A\)to say that\(x\)is an element of\(A\).

Simplify the expression

In this case, the projection is \({P_{1,2,4}}\), which means that only the Ist, 2nd and 4th component are kept.

Let us reduce table 8 such that only have the lst, 2nd and 4th column of the table:

\({\rm{Airline}}\)	\({\rm{Flight number}}\)	\({\rm{Destination}}\)
\({\rm{Nadir}}\)	\(122\)	\({\rm{Detroit}}\)
\({\rm{Acme}}\)	\(221\)	\({\rm{ Denver }}\)
\({\rm{ Acme }}\)	\(122\)	\({\rm{ Anchorage }}\)
\({\rm{ Acme }}\)	\(323\)	\({\rm{ Honolulu }}\)
\({\rm{ Nadir }}\)	\(199\)	\({\rm{ Detroit }}\)
\({\rm{ Acme }}\)	\(222\)	\({\rm{ Denver }}\)
\({\rm{ Nadir }}\)	\(322\)	\({\rm{ Detroit }}\)

The \(n\)-tuples are then:

(Nadir, 122, Detroit)

(Acme, 221, Denver)

(Acme, 122, Anchorage)

(Acme, 323, Honolulu)

(Nadir, 199, Detroit)

(Acme, 222, Denver)

(Nadir, 322, Detroit)