Perfect ruler

A perfect ruler of length

is a ruler with integer markings

= ℓ

, for which there exists an integer

such that any positive integer

is uniquely expressed as the difference

An optimal perfect ruler is one of the smallest length for fixed values of

A 4-perfect ruler of length

To verify this, we need to show that every positive integer

is uniquely expressed as the difference of two markings: This article incorporates material from perfect ruler on PlanetMath, which is licensed under the Creative Commons Attribution/Share-Alike License.

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