Stable Fixed Points of Card Trick Functions

Jyoti Champanerkar; Mahendra Jani

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arXiv · 1308.3396

Stable Fixed Points of Card Trick Functions

Jyoti Champanerkar·Mahendra Jani

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Abstract

The 21-card trick is a way of dealing cards in order to predict the card selected by a volunteer. We give a mathematical explanation of why the well-known 21-card trick works using a simple linear discrete function. The function has a stable fixed point which corresponds to the position where the selected card reaches at the end of the trick. We then generalize the 21(7 x 3)-card trick to a p x q - card trick where p and q are odd integers greater than or equal to three, determine the fixed point and prove that it is also stable.

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Jyoti Champanerkar, Mahendra Jani. 2013-08-13. Stable Fixed Points of Card Trick Functions. https://arxiv.org/abs/1308.3396

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