The following charts depict details of research papers written by four authors, Arman, Brajen, Chintan, and Devon. The papers were of four types, single-author, two-author, three-author, and four-author, that is, written by one, two, three, or all four of these authors, respectively. No other authors were involved in writing these papers. 
The following additional facts are known.
1. Each of the authors wrote at least one of each of the four types of papers.
2. The four authors wrote different numbers of single-author papers.
3. Both Chintan and Devon wrote more three-author papers than Brajen.
4. The number of single-author and two-author papers written by Brajen were the same.
| Author | Single-author | Two-author | Three-author | Four-author |
|---|---|---|---|---|
| Arman | 1 | 5 | 1 | 1 |
| Brajen | 2 | 2 | 2/3 | 1 |
| Chintan | 3 | 2 | 3/4 | 1 |
| Devon | 4 | 1 | 3 | 1 |
Given the information:
Evaluate the number of three-author papers Brajen wrote:
The number of two-author and three-author papers written by Brajen is 4, meeting all criteria.

To determine which statement is necessarily true, let's analyze the given data related to the research papers written by the authors, Arman, Brajen, Chintan, and Devon. We have a list of constraints and information given through bullet points and a chart (which is not visible but assumed to be part of the exercise).
To evaluate which statement is necessarily true:
Given the constraints, there are no definitive numbers provided in the scenario that allow us to conclude that Chintan wrote exactly three two-author papers (Statement i) or more single-author papers than Devon (Statement ii). Thus, neither statement can be concluded as necessarily true based on the given information.
Therefore, the correct choice is:
Neither i nor ii
To solve this question, we need to analyze the provided data on research papers written by the four authors: Arman, Brajen, Chintan, and Devon. We will use the given details and the additional facts to determine the veracity of the statements.
We are given the following additional facts:
Now, analyze the information:
From the analysis above, both statements i and ii are consistent with the given facts, making them necessarily true.
Conclusion: The correct answer is \({\text{Both i and ii}}\).
Step 1: Interpret the given condition. The problem introduces an additional condition that Devon wrote more than one two-author paper, that is, \[ s2_d > 1. \] Under this condition, we are required to determine the number of two-author papers written by Chintan, denoted by \(s2_c\). Step 2: Refer to the uniquely determined distribution. A complete and consistent logical analysis of all the given rules leads to a single feasible table of paper distributions. This table satisfies every constraint in the problem and resolves the apparent inconsistencies present in the data. Step 3: Verify the condition. From the unique solution table, the number of two-author papers written by Devon is \[ s2_d = 2. \] Since \(2 > 1\), the given condition is satisfied by this solution. Step 4: Identify the required value. In the same solution table, the number of two-author papers written by Chintan is \[ s2_c = 3. \] Step 5: Conclusion. Therefore, when Devon has written more than one two-author paper, the corresponding number of two-author papers written by Chintan is \[ 3. \]

For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is: