Ceiling of Number plus Integer

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Theorem

$\forall n \in \Z: \ceiling x + n = \ceiling {x + n}$

where $\ceiling x$ denotes the ceiling of $x$.


Proof

\(\ds \ceiling {x + n} - 1\) \(<\) \(\, \ds x + n \, \) \(\, \ds \le \, \) \(\ds \ceiling {x + n}\) Number is between Ceiling and One Less
\(\ds \leadsto \ \ \) \(\ds \ceiling {x + n} - n - 1\) \(<\) \(\, \ds x \, \) \(\, \ds \le \, \) \(\ds \ceiling {x + n} - n\)
\(\ds \leadsto \ \ \) \(\ds \ceiling x\) \(=\) \(\ds \ceiling {x + n} - n\) Number is between Ceiling and One Less
\(\ds \leadsto \ \ \) \(\ds \ceiling {x + n}\) \(=\) \(\ds \ceiling x + n\) adding $n$ to both sides

$\blacksquare$


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