Theorem: Int.lt_zpow_succ_log_self
File: Mathlib/Data/Int/Log.lean

tactic: cases' le_or_lt r 0 with hr hr
state_before: R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
⊢ r < ↑b ^ (log b r + 1)

tactic: cases' le_or_lt 1 r with hr1 hr1
state_before: case inr
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
⊢ r < ↑b ^ (log b r + 1)

tactic: rw [log_of_right_le_zero _ hr, zero_add, zpow_one]
state_before: case inl
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : r ≤ 0
⊢ r < ↑b ^ (log b r + 1)

tactic: exact hr.trans_lt (zero_lt_one.trans_le <| by exact_mod_cast hb.le)
state_before: case inl
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : r ≤ 0
⊢ r < ↑b

tactic: exact_mod_cast hb.le
state_before: R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : r ≤ 0
⊢ 1 ≤ ↑b

tactic: rw [log_of_one_le_right _ hr1]
state_before: case inr.inl
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : 1 ≤ r
⊢ r < ↑b ^ (log b r + 1)

tactic: rw [Int.ofNat_add_one_out, zpow_ofNat, ← Nat.cast_pow]
state_before: case inr.inl
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : 1 ≤ r
⊢ r < ↑b ^ (↑(Nat.log b ⌊r⌋₊) + 1)

tactic: apply Nat.lt_of_floor_lt
state_before: case inr.inl
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : 1 ≤ r
⊢ r < ↑(b ^ Nat.succ (Nat.log b ⌊r⌋₊))

tactic: exact Nat.lt_pow_succ_log_self hb _
state_before: case inr.inl.h
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : 1 ≤ r
⊢ ⌊r⌋₊ < b ^ Nat.succ (Nat.log b ⌊r⌋₊)

tactic: rw [log_of_right_le_one _ hr1.le]
state_before: case inr.inr
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : r < 1
⊢ r < ↑b ^ (log b r + 1)

tactic: have hcri : 1 < r⁻¹ := one_lt_inv hr hr1
state_before: case inr.inr
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : r < 1
⊢ r < ↑b ^ (-↑(Nat.clog b ⌈r⁻¹⌉₊) + 1)

tactic: have : 1 ≤ Nat.clog b ⌈r⁻¹⌉₊ :=
  Nat.succ_le_of_lt (Nat.clog_pos hb <| Nat.one_lt_cast.1 <| hcri.trans_le (Nat.le_ceil _))
state_before: case inr.inr
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : r < 1
hcri : 1 < r⁻¹
⊢ r < ↑b ^ (-↑(Nat.clog b ⌈r⁻¹⌉₊) + 1)

tactic: rw [neg_add_eq_sub, ← neg_sub, ← Int.ofNat_one, ← Int.ofNat_sub this, zpow_neg, zpow_ofNat,
  lt_inv hr (pow_pos (Nat.cast_pos.mpr <| zero_lt_one.trans hb) _), ← Nat.cast_pow]
state_before: case inr.inr
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : r < 1
hcri : 1 < r⁻¹
this : 1 ≤ Nat.clog b ⌈r⁻¹⌉₊
⊢ r < ↑b ^ (-↑(Nat.clog b ⌈r⁻¹⌉₊) + 1)

tactic: refine' Nat.lt_ceil.1 _
state_before: case inr.inr
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : r < 1
hcri : 1 < r⁻¹
this : 1 ≤ Nat.clog b ⌈r⁻¹⌉₊
⊢ ↑(b ^ (Nat.clog b ⌈r⁻¹⌉₊ - 1)) < r⁻¹

tactic: exact Nat.pow_pred_clog_lt_self hb <| Nat.one_lt_cast.1 <| hcri.trans_le <| Nat.le_ceil _
state_before: case inr.inr
R : Type u_1
inst✝¹ : LinearOrderedSemifield R
inst✝ : FloorSemiring R
b : ℕ
hb : 1 < b
r : R
hr : 0 < r
hr1 : r < 1
hcri : 1 < r⁻¹
this : 1 ≤ Nat.clog b ⌈r⁻¹⌉₊
⊢ b ^ (Nat.clog b ⌈r⁻¹⌉₊ - 1) < ⌈r⁻¹⌉₊