Induction: Each square can be covered by L-stones

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    Induction Square
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Discussion Overview

The discussion revolves around a mathematical problem involving the covering of a square with side length $2^n$ units using L-stones after removing one corner sub-square. Participants explore the application of induction to demonstrate that the remaining area can be completely covered without overlapping.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant presents the problem of covering a square of side length $2^n$ with L-stones after removing a corner sub-square and seeks to verify their drawing for the first three cases.
  • Another participant questions whether the sketch from case $n=2$ can be used to derive the solution for case $n=3$, suggesting a potential approach to filling the sub-squares.
  • There is a discussion about aligning the remaining cells in case $n=3$ to fit another L-stone, with participants considering the arrangement of empty cells.
  • Participants discuss the necessity of positioning the empty cell in a way that allows the remaining empty cells to form an L-shape, which would accommodate another L-stone.

Areas of Agreement / Disagreement

Participants express a general agreement on the approach of using the case $n=2$ to inform the case $n=3$, but the discussion remains exploratory without a definitive conclusion on the method's validity.

Contextual Notes

Participants do not resolve the specifics of how to align the empty cells or the implications of their arrangements, leaving some assumptions and steps in the reasoning process unaddressed.

mathmari
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Hey! :o

A square with the side length $2^n$ length units (LU) is divided in sub-squares with the side length $1$. One of the sub-squares in the corners has been removed. All other sub-squares should now be covered completely and without overlapping with L-stones. An L-stone consists of three sub-squares that together form an L.

I want to draw the problem for the first three cases described above ($1 \leq n \leq 3$). Then I want to show the following using induction:

For all $n \in N$ the square with side length $2^n$ LU can be covered completely and without overlapping with L-stones, after one of the sub-squares in the corners has been removed.
For the first part:

View attachment 9354

Is the drawing correct? (Wondering)
 

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Can we use the sketch of the case $n=2$ to get the one of the case $n=3$ ? (Wondering)

Is it maybe as follows?

The upper right sub-square is the one of case $n=2$. For the other sub-squares we have to fill them completely.

(Wondering)
 
mathmari said:
Can we use the sketch of the case $n=2$ to get the one of the case $n=3$ ? (Wondering)

Is it maybe as follows?

The upper right sub-square is the one of case $n=2$. For the other sub-squares we have to fill them completely.

Hey mathmari!

I think so yes.
Suppose we use the same case $n=2$ square to fill each of the 4 sub squares of the case $n=3$.
Then we have 3 cells left that we still have to fill don't we?
Can we align them so that we can put another L-square into it? (Wondering)
 
Klaas van Aarsen said:
I think so yes.
Suppose we use the same case $n=2$ square to fill each of the 4 sub squares of the case $n=3$.
Then we have 3 cells left that we still have to fill don't we?
Can we align them so that we can put another L-square into it? (Wondering)

To do that we have to make the empty cell in that corner so that the three empty cells make a L, or not? (Wondering)
 
mathmari said:
To do that we have to make the empty cell in that corner so that the three empty cells make a L, or not?

Yes. So the sub squares at left-top, left-bottom, and right-bottom would have their empty cell at the center.
Those empty cells have the shape of an L then, allowing for another piece. (Thinking)
 
Klaas van Aarsen said:
Yes. So the sub squares at left-top, left-bottom, and right-bottom would have their empty cell at the center.
Those empty cells have the shape of an L then, allowing for another piece. (Thinking)

I see! Thanks a lot! (Mmm)
 

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