问题

You are supposed to provide a solution to a given problem.

Problem:
Is there an eigenbasis for the identity matrix I_n?
Solution:

答案

模型 模型答案 正确答案
金声玉亮2.0 Yes, there is an eigenbasis for the identity matrix \(I_n\).

Explanation:
An eigenbasis of a matrix is a basis for the vector space consisting of eigenvectors of that matrix. For a matrix to have an eigenbasis, it needs to be diagonalizable, meaning it can be expressed as \(A = PDP^{-1}\), where \(D\) is a diagonal matrix whose diagonal entries are the eigenvalues of \(A\), and \(P\) is the matrix whose columns are the eigenvectors of \(A\).

The identity matrix \(I_n\) is a diagonal matrix with all diagonal entries equal to 1. Therefore, its eigenvalues are all 1, and any non-zero vector is an eigenvector of \(I_n\) since \(I_n v = v\) for any non-zero vector \(v\). As a result, any basis of the vector space can be chosen as an eigenbasis for \(I_n\), since all vectors in the basis will be eigenvectors of \(I_n\).

In summary, any basis of the vector space \(\mathbb{R}^n\) (or whatever the underlying vector space is) can serve as an eigenbasis for the identity matrix \(I_n\).
True
deepseekr1

The identity matrix \( I_n \) does have an eigenbasis.

**Reasoning:**
1. **Eigenvectors of \( I_n \):** Every non-zero vector \( v \) in the vector space is an eigenvector of \( I_n \), since \( I_n v = v \), with eigenvalue \( 1 \).
2. **Eigenspace:** The eigenspace for the eigenvalue \( 1 \) is the entire vector space, as \( (I_n - I_n)v = 0 \) holds for all \( v \). Thus, the geometric multiplicity of the eigenvalue \( 1 \) is \( n \).
3. **Diagonalizability:** A matrix is diagonalizable if its eigenvectors form a basis (an eigenbasis). Since every basis of the vector space consists of eigenvectors of \( I_n \), such a basis exists. For example, the standard basis \( \{e_1, e_2, \dots, e_n\} \) is already an eigenbasis.

**Conclusion:** Yes, there exists an eigenbasis for \( I_n \). In fact, every basis of the vector space is an eigenbasis for the identity matrix.

\(\boxed{\text{Yes}}\)
True
gpto1 Yes, there is an eigenbasis for the identity matrix \( I_n \). In fact, every non-zero vector in \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)) is an eigenvector of the identity matrix, corresponding to the eigenvalue \( \lambda = 1 \).

### Explanation:

The identity matrix \( I_n \) is a square \( n \times n \) matrix with ones on the main diagonal and zeros elsewhere:

\[
I_n = \begin{pmatrix}
1 & 0 & 0 & \dots & 0 \\
0 & 1 & 0 & \dots & 0 \\
0 & 0 & 1 & \dots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
0 & 0 & 0 & \dots & 1 \\
\end{pmatrix}
\]

An **eigenvector** \( \mathbf{v} \) of a matrix \( A \) is a non-zero vector that satisfies the equation:

\[
A\mathbf{v} = \lambda \mathbf{v}
\]

where \( \lambda \) is the **eigenvalue** corresponding to \( \mathbf{v} \).

#### For the Identity Matrix:

1. **Eigenvalue Determination**:

Let's find the eigenvalues by solving the characteristic equation:

\[
\det(I_n - \lambda I_n) = 0
\]

Simplify \( I_n - \lambda I_n = (1 - \lambda)I_n \).

The determinant of \( (1 - \lambda)I_n \) is:

\[
\det((1 - \lambda)I_n) = (1 - \lambda)^n \det(I_n) = (1 - \lambda)^n (1) = (1 - \lambda)^n
\]

Setting the determinant to zero:

\[
(1 - \lambda)^n = 0 \implies \lambda = 1
\]

So, the only eigenvalue of \( I_n \) is \( \lambda = 1 \), and its algebraic multiplicity is \( n \).

2. **Eigenvector Determination**:

For \( \lambda = 1 \), the eigenvector equation becomes:

\[
I_n \mathbf{v} = \mathbf{v}
\]

Which simplifies to:

\[
\mathbf{v} = \mathbf{v}
\]

This equation is always true for any vector \( \mathbf{v} \) in \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)). However, since eigenvectors are defined as **non-zero** vectors, every non-zero vector in \( \mathbb{R}^n \) is an eigenvector corresponding to the eigenvalue \( \lambda = 1 \).

3. **Existence of an Eigenbasis**:

An eigenbasis is a basis for the vector space consisting entirely of eigenvectors of the matrix. Since every non-zero vector is an eigenvector of \( I_n \), any basis of \( \mathbb{R}^n \) is an eigenbasis for \( I_n \).

For example, consider the standard basis vectors in \( \mathbb{R}^n \):

\[
\mathbf{e}_1 = \begin{pmatrix}1 \\ 0 \\ \vdots \\ 0\end{pmatrix}, \quad \mathbf{e}_2 = \begin{pmatrix}0 \\ 1 \\ \vdots \\ 0\end{pmatrix}, \quad \dots, \quad \mathbf{e}_n = \begin{pmatrix}0 \\ 0 \\ \vdots \\ 1\end{pmatrix}
\]

Since \( I_n \mathbf{e}_i = \mathbf{e}_i \) for each \( i = 1, 2, \dots, n \), the set \( \{ \mathbf{e}_1, \mathbf{e}_2, \dots, \mathbf{e}_n \} \) forms an eigenbasis for \( I_n \).

### Conclusion:

Yes, there exists an eigenbasis for the identity matrix \( I_n \). In fact, any basis of the vector space \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)) serves as an eigenbasis for \( I_n \), since all non-zero vectors are eigenvectors corresponding to the eigenvalue \( \lambda = 1 \).
True
GPT-4o Yes, there is an eigenbasis for the identity matrix \( I_n \).

To understand why, let's break it down step-by-step:

1. **Eigenvalues of the Identity Matrix:**
The identity matrix \( I_n \) is a square matrix where all the diagonal elements are 1, and all off-diagonal elements are 0. The eigenvalue equation for a matrix \( A \) is given by:
\[
A \mathbf{v} = \lambda \mathbf{v}
\]
For the identity matrix \( I_n \), this becomes:
\[
I_n \mathbf{v} = \lambda \mathbf{v}
\]
Since \( I_n \mathbf{v} = \mathbf{v} \) for any vector \( \mathbf{v} \), it follows that:
\[
\mathbf{v} = \lambda \mathbf{v}
\]
This implies that \( \lambda \) must be 1. Thus, the only eigenvalue of the identity matrix \( I_n \) is \( \lambda = 1 \).

2. **Eigenvectors of the Identity Matrix:**
Given that the eigenvalue \( \lambda = 1 \), the eigenvector equation becomes:
\[
I_n \mathbf{v} = 1 \cdot \mathbf{v}
\]
This equation is satisfied by any non-zero vector \( \mathbf{v} \) in \( \mathbb{R}^n \). Therefore, every non-zero vector in \( \mathbb{R}^n \) is an eigenvector of \( I_n \) corresponding to the eigenvalue 1.

3. **Eigenbasis:**
An eigenbasis for a matrix is a basis for the vector space consisting of eigenvectors of the matrix. Since every non-zero vector in \( \mathbb{R}^n \) is an eigenvector of \( I_n \) with eigenvalue 1, we can choose the standard basis vectors \( \mathbf{e}_1, \mathbf{e}_2, \ldots, \mathbf{e}_n \) of \( \mathbb{R}^n \) as our eigenbasis. These standard basis vectors are:
\[
\mathbf{e}_1 = \begin{pmatrix} 1 \\ 0 \\ 0 \\ \vdots \\ 0 \end{pmatrix}, \quad \mathbf{e}_2 = \begin{pmatrix} 0 \\ 1 \\ 0 \\ \vdots \\ 0 \end{pmatrix}, \quad \ldots, \quad \mathbf{e}_n = \begin{pmatrix} 0 \\ 0 \\ 0 \\ \vdots \\ 1 \end{pmatrix}
\]
Each of these vectors satisfies:
\[
I_n \mathbf{e}_i = \mathbf{e}_i
\]
for \( i = 1, 2, \ldots, n \), confirming that they are eigenvectors corresponding to the eigenvalue 1.

Therefore, the set \( \{ \mathbf{e}_1, \mathbf{e}_2, \ldots, \mathbf{e}_n \} \) forms an eigenbasis for the identity matrix \( I_n \).
True
llama3.1-70B-Instruct

Yes, there is an eigenbasis for the identity matrix I_n.

The identity matrix I_n is a diagonal matrix with all diagonal entries equal to 1. Therefore, all the eigenvalues of I_n are 1.

To find the eigenvectors of I_n, we need to solve the equation:

I_n v = λ v

where v is an eigenvector and λ is an eigenvalue.

Since all the eigenvalues of I_n are 1, we can write:

I_n v = v

This equation is satisfied for any vector v, since the identity matrix I_n does not change the vector v.

Therefore, every vector v is an eigenvector of I_n, and the set of all vectors v forms an eigenbasis for I_n.

In other words, the identity matrix I_n has an eigenbasis consisting of all vectors in the vector space, and the corresponding eigenvalues are all equal to 1.
True
llama3.1-405B-Instruct

Yes, there is an eigenbasis for the identity matrix I_n.

The identity matrix I_n has n eigenvalues, all of which are equal to 1. The corresponding eigenvectors are the standard basis vectors of R^n, which are:

e_1 = (1, 0, 0, ..., 0)
e_2 = (0, 1, 0, ..., 0)
...
e_n = (0, 0, 0, ..., 1)

These eigenvectors are linearly independent and span R^n, so they form a basis for R^n. Therefore, the identity matrix I_n has an eigenbasis consisting of the standard basis vectors of R^n.
True
DeepSeek-Coder-V2 Yes, there is an eigenbasis for the identity matrix \( I_n \).

To understand this, let's first recall some basic definitions and properties:

1. **Identity Matrix \( I_n \)**: This is an \( n \times n \) matrix with ones on the diagonal and zeros elsewhere. It is denoted as \( I_n \).

2. **Eigenvalue and Eigenvector**: For a matrix \( A \), a scalar \( \lambda \) is called an eigenvalue and a non-zero vector \( v \) is called an eigenvector if they satisfy the equation \( Av = \lambda v \).

3. **Eigenbasis**: An eigenbasis is a basis for the vector space consisting entirely of eigenvectors.

Now, let's analyze the identity matrix \( I_n \):

- The identity matrix \( I_n \) has all its diagonal entries as 1, and all off-diagonal entries as 0.
- For any vector \( v \) in \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)), multiplying \( v \) by \( I_n \) results in \( I_n v = v \).

This implies that every non-zero vector \( v \) in \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)) is an eigenvector of \( I_n \) with eigenvalue 1. Specifically:

\[ I_n v = 1 \cdot v \]

Since every non-zero vector in \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)) is an eigenvector of \( I_n \) with eigenvalue 1, we can choose any basis for \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)), and this basis will consist entirely of eigenvectors of \( I_n \).

Therefore, there exists an eigenbasis for the identity matrix \( I_n \). For example, the standard basis vectors \( \{e_1, e_2, \ldots, e_n\} \) where \( e_i \) is the vector with 1 in the \( i \)-th position and 0 elsewhere, form an eigenbasis for \( I_n \).

In conclusion, the answer to the problem is yes, there is an eigenbasis for the identity matrix \( I_n \).
True
Qwen2-72B-Instruct Yes, there is an eigenbasis for the identity matrix \(I_n\).

Explanation:
An eigenbasis of a matrix is a basis for the vector space consisting of eigenvectors of that matrix. For a matrix to have an eigenbasis, it needs to be diagonalizable, meaning it can be expressed as \(A = PDP^{-1}\), where \(D\) is a diagonal matrix whose diagonal entries are the eigenvalues of \(A\), and \(P\) is the matrix whose columns are the eigenvectors of \(A\).

The identity matrix \(I_n\) is a diagonal matrix with all diagonal entries equal to 1. Therefore, its eigenvalues are all 1, and any non-zero vector is an eigenvector of \(I_n\) since \(I_n v = v\) for any non-zero vector \(v\). As a result, any basis of the vector space can be chosen as an eigenbasis for \(I_n\), since all vectors in the basis will be eigenvectors of \(I_n\).

In summary, any basis of the vector space \(\mathbb{R}^n\) (or whatever the underlying vector space is) can serve as an eigenbasis for the identity matrix \(I_n\).
True
baichuan4 Yes, there is an eigenbasis for the identity matrix $I_n$.

An eigenbasis of a matrix is a basis consisting of the eigenvectors of the matrix. For the identity matrix $I_n$, every non-zero vector is an eigenvector with the corresponding eigenvalue of 1. This is because multiplying any vector by the identity matrix results in the same vector:

$$I_n \mathbf{v} = \mathbf{v}$$

Therefore, any set of $n$ linearly independent vectors in $\mathbb{R}^n$ (or $\mathbb{C}^n$) can serve as an eigenbasis for $I_n$. A standard choice for this basis is the set of standard basis vectors $e_1, e_2, \ldots, e_n$, where $e_i$ is the vector with a 1 in the $i$-th position and 0s elsewhere. However, any other set of linearly independent vectors would also form an eigenbasis for $I_n$.
True
doubao The identity matrix I_n has n linearly independent eigenvectors, which can form an eigenbasis. The eigenvectors of I_n are the standard basis vectors e_i (where i = 1, 2,..., n), and the corresponding eigenvalue for each eigenvector is 1. So, yes, there is an eigenbasis for the identity matrix I_n. True
minimax An eigenbasis for a matrix is a set of eigenvectors that form a basis for the vector space in which the matrix operates. The identity matrix \( I_n \) is an \( n \times n \) matrix with ones on the diagonal and zeros elsewhere. Mathematically, it is defined as:

\[ I_n = \begin{bmatrix}
1 & 0 & \cdots & 0 \\
0 & 1 & \cdots & 0 \\
\vdots & \vdots & \ddots & \vdots \\
0 & 0 & \cdots & 1
\end{bmatrix} \]

The eigenvalues of the identity matrix \( I_n \) are all equal to 1. This is because if you multiply \( I_n \) by any vector \( \mathbf{v} \), you get \( I_n \mathbf{v} = \mathbf{v} \), which means that the vector \( \mathbf{v} \) is an eigenvector corresponding to the eigenvalue \( \lambda = 1 \).

Since the identity matrix is diagonal, its eigenvectors are simply the standard basis vectors of the space. For \( \mathbb{R}^n \), these are:

\[ \mathbf{e}_1 = \begin{bmatrix} 1 \\ 0 \\ \vdots \\ 0 \end{bmatrix}, \mathbf{e}_2 = \begin{bmatrix} 0 \\ 1 \\ \vdots \\ 0 \end{bmatrix}, \ldots, \mathbf{e}_n = \begin{bmatrix} 0 \\ 0 \\ \vdots \\ 1 \end{bmatrix} \]

Each of these vectors is an eigenvector of \( I_n \) corresponding to the eigenvalue 1. Since there are \( n \) such eigenvectors and they are linearly independent, they form a basis for \( \mathbb{R}^n \). Therefore, the standard basis is an eigenbasis for the identity matrix \( I_n \).

In conclusion, yes, there is an eigenbasis for the identity matrix \( I_n \), and it is the standard basis of the vector space.
True
kimi Yes, there is an eigenbasis for the identity matrix \( I_n \).

**Solution:**

1. **Eigenvalues of Identity Matrix:**
The identity matrix \( I_n \) is a square matrix of size \( n \times n \) with ones on the diagonal and zeros elsewhere. For any vector \( v \) that is not the zero vector, the product \( I_n \cdot v \) will result in the same vector \( v \). This means that the identity matrix acts as the multiplicative identity for vectors, just like the number 1 acts as the multiplicative identity for numbers.

2. **Eigenvectors:**
For a matrix \( A \), a vector \( v \) is an eigenvector if there exists a scalar \( \lambda \) such that \( A \cdot v = \lambda \cdot v \). Here, \( \lambda \) is called the eigenvalue corresponding to the eigenvector \( v \).

3. **Eigenbasis for \( I_n \):**
For the identity matrix \( I_n \), every non-zero vector \( v \) in \( \mathbb{R}^n \) is an eigenvector with the eigenvalue \( \lambda = 1 \). This is because \( I_n \cdot v = v \), which satisfies the eigenvector equation with \( \lambda = 1 \).

4. **Constructing the Eigenbasis:**
The standard basis vectors of \( \mathbb{R}^n \), which are the vectors \( e_1, e_2, \ldots, e_n \) where each \( e_i \) has a 1 in the \( i \)-th position and zeros elsewhere, are all eigenvectors of \( I_n \) with eigenvalue 1.

5. **Conclusion:**
Since every standard basis vector is an eigenvector of \( I_n \) with eigenvalue 1, and these vectors form a basis for \( \mathbb{R}^n \), they constitute an eigenbasis for \( I_n \). This eigenbasis is orthogonal and spans the entire space \( \mathbb{R}^n \).

Thus, the identity matrix \( I_n \) has an eigenbasis consisting of its standard basis vectors, each with eigenvalue 1.
True
wenxinyiyan Yes, there is an eigenbasis for the identity matrix I_n.

To see this, consider any nonzero vector v in R^n. We have:

I_n * v = v

This means that v is an eigenvector of I_n with eigenvalue 1. Since we can choose any nonzero vector in R^n to be an eigenvector, and these vectors will span R^n, we can construct an eigenbasis for I_n.

Specifically, let {v_1, v_2, ..., v_n} be any basis for R^n (for example, the standard basis). Then each v_i is an eigenvector of I_n with eigenvalue 1, and {v_1, v_2, ..., v_n} is an eigenbasis for I_n.
True
zhipu Yes, there is an eigenbasis for the identity matrix \( I_n \).

To understand why, let's first recall some definitions:

1. **Eigenvalue and Eigenvector**: For a square matrix \( A \), a non-zero vector \( v \) is called an eigenvector if there exists a scalar \( \lambda \) (called the eigenvalue) such that \( A v = \lambda v \).

2. **Eigenbasis**: A set of eigenvectors of a matrix that forms a basis for the vector space.

Now, let's consider the identity matrix \( I_n \), which is an \( n \times n \) matrix with 1's on the diagonal and 0's elsewhere.

### Eigenvalues of \( I_n \)

For the identity matrix \( I_n \), any vector \( v \) satisfies:
\[ I_n v = v \]

This implies that every non-zero vector \( v \) is an eigenvector corresponding to the eigenvalue \( \lambda = 1 \). Therefore, the only eigenvalue of \( I_n \) is 1, and it has multiplicity \( n \).

### Eigenvectors of \( I_n \)

Since every non-zero vector \( v \) in \( \mathbb{R}^n \) satisfies \( I_n v = v \), every non-zero vector in \( \mathbb{R}^n \) is an eigenvector corresponding to the eigenvalue 1.

### Eigenbasis for \( I_n \)

To form an eigenbasis, we need \( n \) linearly independent eigenvectors. In the case of \( I_n \), we can choose any set of \( n \) linearly independent vectors in \( \mathbb{R}^n \). A common choice is the standard basis \( \{e_1, e_2, \ldots, e_n\} \), where:
\[ e_1 = \begin{pmatrix} 1 \\ 0 \\ \vdots \\ 0 \end{pmatrix}, \quad e_2 = \begin{pmatrix} 0 \\ 1 \\ \vdots \\ 0 \end{pmatrix}, \quad \ldots, \quad e_n = \begin{pmatrix} 0 \\ 0 \\ \vdots \\ 1 \end{pmatrix} \]

These vectors are linearly independent and span \( \mathbb{R}^n \), thus forming a basis. Since each \( e_i \) is an eigenvector of \( I_n \) corresponding to the eigenvalue 1, \( \{e_1, e_2, \ldots, e_n\} \) is an eigenbasis for \( I_n \).

### Conclusion

Therefore, there is indeed an eigenbasis for the identity matrix \( I_n \), and any set of \( n \) linearly independent vectors in \( \mathbb{R}^n \) can serve as such an eigenbasis. The standard basis \( \{e_1, e_2, \ldots, e_n\} \) is a straightforward example of such an eigenbasis.
True
gpto1 Yes, there is an eigenbasis for the identity matrix \( I_n \). In fact, every non-zero vector in \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)) is an eigenvector of the identity matrix, corresponding to the eigenvalue \( \lambda = 1 \).

### Explanation:

The identity matrix \( I_n \) is a square \( n \times n \) matrix with ones on the main diagonal and zeros elsewhere:

\[
I_n = \begin{pmatrix}
1 & 0 & 0 & \dots & 0 \\
0 & 1 & 0 & \dots & 0 \\
0 & 0 & 1 & \dots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
0 & 0 & 0 & \dots & 1 \\
\end{pmatrix}
\]

An **eigenvector** \( \mathbf{v} \) of a matrix \( A \) is a non-zero vector that satisfies the equation:

\[
A\mathbf{v} = \lambda \mathbf{v}
\]

where \( \lambda \) is the **eigenvalue** corresponding to \( \mathbf{v} \).

#### For the Identity Matrix:

1. **Eigenvalue Determination**:

Let's find the eigenvalues by solving the characteristic equation:

\[
\det(I_n - \lambda I_n) = 0
\]

Simplify \( I_n - \lambda I_n = (1 - \lambda)I_n \).

The determinant of \( (1 - \lambda)I_n \) is:

\[
\det((1 - \lambda)I_n) = (1 - \lambda)^n \det(I_n) = (1 - \lambda)^n (1) = (1 - \lambda)^n
\]

Setting the determinant to zero:

\[
(1 - \lambda)^n = 0 \implies \lambda = 1
\]

So, the only eigenvalue of \( I_n \) is \( \lambda = 1 \), and its algebraic multiplicity is \( n \).

2. **Eigenvector Determination**:

For \( \lambda = 1 \), the eigenvector equation becomes:

\[
I_n \mathbf{v} = \mathbf{v}
\]

Which simplifies to:

\[
\mathbf{v} = \mathbf{v}
\]

This equation is always true for any vector \( \mathbf{v} \) in \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)). However, since eigenvectors are defined as **non-zero** vectors, every non-zero vector in \( \mathbb{R}^n \) is an eigenvector corresponding to the eigenvalue \( \lambda = 1 \).

3. **Existence of an Eigenbasis**:

An eigenbasis is a basis for the vector space consisting entirely of eigenvectors of the matrix. Since every non-zero vector is an eigenvector of \( I_n \), any basis of \( \mathbb{R}^n \) is an eigenbasis for \( I_n \).

For example, consider the standard basis vectors in \( \mathbb{R}^n \):

\[
\mathbf{e}_1 = \begin{pmatrix}1 \\ 0 \\ \vdots \\ 0\end{pmatrix}, \quad \mathbf{e}_2 = \begin{pmatrix}0 \\ 1 \\ \vdots \\ 0\end{pmatrix}, \quad \dots, \quad \mathbf{e}_n = \begin{pmatrix}0 \\ 0 \\ \vdots \\ 1\end{pmatrix}
\]

Since \( I_n \mathbf{e}_i = \mathbf{e}_i \) for each \( i = 1, 2, \dots, n \), the set \( \{ \mathbf{e}_1, \mathbf{e}_2, \dots, \mathbf{e}_n \} \) forms an eigenbasis for \( I_n \).

### Conclusion:

Yes, there exists an eigenbasis for the identity matrix \( I_n \). In fact, any basis of the vector space \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)) serves as an eigenbasis for \( I_n \), since all non-zero vectors are eigenvectors corresponding to the eigenvalue \( \lambda = 1 \).
True
deepseekv3 Yes, there is an eigenbasis for the identity matrix \( I_n \). Here's why:

1. **Eigenvalues of \( I_n \)**:
The identity matrix \( I_n \) has only one eigenvalue: \( \lambda = 1 \). This is because for any vector \( \mathbf{v} \), \( I_n \mathbf{v} = \mathbf{v} \).

2. **Eigenspace**:
The eigenspace corresponding to \( \lambda = 1 \) is the entire vector space \( \mathbb{R}^n \) (or \( \mathbb{C}^n \), depending on the field), since every vector is an eigenvector of \( I_n \) with eigenvalue \( 1 \).

3. **Eigenbasis**:
Any basis of \( \mathbb{R}^n \) (or \( \mathbb{C}^n \)) is an eigenbasis for \( I_n \). For example, the standard basis \( \{ \mathbf{e}_1, \mathbf{e}_2, \dots, \mathbf{e}_n \} \) is an eigenbasis for \( I_n \), where \( \mathbf{e}_i \) is the vector with a \( 1 \) in the \( i \)-th position and \( 0 \) elsewhere.

Thus, \( I_n \) has an eigenbasis, and in fact, any basis of the vector space serves as an eigenbasis for \( I_n \).
True