Theorem: NonarchimedeanRing.mul_subset
File: Mathlib/Topology/Algebra/Nonarchimedean/Basic.lean

Proof steps:
state_before: R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U : OpenAddSubgroup R
⊢ ∃ V, ↑V * ↑V ⊆ ↑U
state_after: R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
⊢ ∃ V, ↑V * ↑V ⊆ ↑U
tactic: let ⟨V, H⟩ := prod_self_subset <| (U.isOpen.preimage continuous_mul).mem_nhds <| by
    simpa only [Set.mem_preimage, Prod.snd_zero, mul_zero] using U.zero_mem
state_before: R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
⊢ ∃ V, ↑V * ↑V ⊆ ↑U
state_after: case h
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
⊢ ↑V * ↑V ⊆ ↑U
tactic: use V
state_before: case h
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
⊢ ↑V * ↑V ⊆ ↑U
state_after: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
⊢ v ∈ ↑U
tactic: rintro v ⟨a, ha, b, hb, hv⟩
state_before: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
⊢ v ∈ ↑U
state_after: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
hy : (a, b) ∈ (fun p => p.1 * p.2) ⁻¹' ↑U
⊢ v ∈ ↑U
tactic: have hy := H (Set.mk_mem_prod ha hb)
state_before: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
hy : (a, b) ∈ (fun p => p.1 * p.2) ⁻¹' ↑U
⊢ v ∈ ↑U
state_after: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
hy : v ∈ U
⊢ v ∈ ↑U
tactic: simp only [Set.mem_preimage, SetLike.mem_coe, hv] at hy
state_before: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
hy : v ∈ U
⊢ v ∈ ↑U
state_after: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
hy : v ∈ U
⊢ v ∈ U
tactic: rw [SetLike.mem_coe]
state_before: case h.intro.intro.intro.intro
R : Type u_1
S : Type u_2
inst✝⁵ : Ring R
inst✝⁴ : TopologicalSpace R
inst✝³ : NonarchimedeanRing R
inst✝² : Ring S
inst✝¹ : TopologicalSpace S
inst✝ : NonarchimedeanRing S
U V : OpenAddSubgroup R
H : ↑V ×ˢ ↑V ⊆ (fun p => p.1 * p.2) ⁻¹' ↑U
v a : R
ha : a ∈ ↑V
b : R
hb : b ∈ ↑V
hv : (fun x x_1 => x * x_1) a b = v
hy : v ∈ U
⊢ v ∈ U
state_after: no goals
tactic: exact hy