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Exercise 488Combinatorics › Inclusion-exclusionHigh schoolAdded 3 Nov 2026

Surjections to $\{0,1\}$

#surjections#IE#onto

Statement

Count surjections from an nn-element set to a 22-element set.

Hint

Same as non-constant.

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Solution

Same as non-constant. 2n−22^n-2.

Conclusion. 2n−22^n-2 surjections.