English
For fixed b, if n ≤ m then clog_b(n) ≤ clog_b(m).
Русский
Для фиксированного b, если n ≤ m, то clog_b(n) ≤ clog_b(m).
LaTeX
$$$ n \\le m \\implies \\operatorname{clog}_b n \\le \\operatorname{clog}_b m $$$
Lean4
@[mono, gcongr]
theorem clog_mono_right (b : ℕ) {n m : ℕ} (h : n ≤ m) : clog b n ≤ clog b m :=
by
rcases le_or_gt b 1 with hb | hb
· rw [clog_of_left_le_one hb]
exact zero_le _
· rw [clog_le_iff_le_pow hb]
exact h.trans (le_pow_clog hb _)