# Is Cartesian product countable set countable?

## Is Cartesian product countable set countable?

Cartesian products of countable sets: If A and B are countable, then the cartesian product A × B is countable, too.

## Is a Cartesian product of infinite countable sets countable?

The cartesian product of a countably infinite collection of countably infinite sets is uncountable. Let N to be the set of positive integers and consider the cartesian product of countably many copies of N. This is the set S of sequences of positive integers.

How do you prove the Cartesian product of two countable sets is countable?

Assuming that Yk (k ∈ n, 1 ≤ k < n) is countable; Then Yk+1 = ( X1 * X2 * ……. * Xk) * Xk+1 = Yk * Xk+1 where the Yk and the Xk+1 can be called countable. Hence the cartesian product of the countable set is always countable.

Is countable product of countable sets countable?

Originally Answered: Is the countable cartesian product of countable sets countable? No, a Cartesian product of countably infinitely many countable sets (with at least two elements in each) is uncountable.

### What is countable and uncountable set?

A set S is countable if its cardinality |S| is less than or equal to (aleph-null), the cardinality of the set of natural numbers N. A set S is countably infinite if . A set is uncountable if it is not countable, i.e. its cardinality is greater than. ; the reader is referred to Uncountable set for further discussion.

### What is the cartesian product of two sets?

In mathematics, the Cartesian Product of sets A and B is defined as the set of all ordered pairs (x, y) such that x belongs to A and y belongs to B. For example, if A = {1, 2} and B = {3, 4, 5}, then the Cartesian Product of A and B is {(1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5)}.

Is the product of two countable sets countable?

Theorem. The cartesian product of two countable sets is countable.

Is the product of 2 countable sets countable?

#### Why is it called cartesian product?

The Cartesian product is named after René Descartes, whose formulation of analytic geometry gave rise to the concept, which is further generalized in terms of direct product.

#### Which sets are uncountable?

In mathematics, an uncountable set (or uncountably infinite set) is an infinite set that contains too many elements to be countable. The uncountability of a set is closely related to its cardinal number: a set is uncountable if its cardinal number is larger than that of the set of all natural numbers.

Which is a countable set?

The basic examples of (finite) countable sets are sets given by a list of their elements: The set of even prime numbers that contains only one element: {2}. The set of prime numbers less than 10: {2,3,5,7}. The set of diagonals in a regular pentagon ABCDE: {AC,AD,BD,BE,CE}.

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