Theorem: Finsupp.ext_iff'
File: Mathlib/Data/Finsupp/Defs.lean

tactic: classical
exact if h : a ∈ f.support then h₂ a h else by
  have hf : f a = 0 := not_mem_support_iff.1 h
  have hg : g a = 0 := by rwa [h₁, not_mem_support_iff] at h
  rw [hf, hg]
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
⊢ f a = g a
state_after: no goals

tactic: exact if h : a ∈ f.support then h₂ a h else by
  have hf : f a = 0 := not_mem_support_iff.1 h
  have hg : g a = 0 := by rwa [h₁, not_mem_support_iff] at h
  rw [hf, hg]
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
⊢ f a = g a
state_after: no goals

tactic: have hf : f a = 0 := not_mem_support_iff.1 h
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
h : a ∉ f.support
⊢ f a = g a
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
h : a ∉ f.support
hf : f a = 0
⊢ f a = g a

tactic: have hg : g a = 0 := by rwa [h₁, not_mem_support_iff] at h
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
h : a ∉ f.support
hf : f a = 0
⊢ f a = g a
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
h : a ∉ f.support
hf : f a = 0
hg : g a = 0
⊢ f a = g a

tactic: rw [hf, hg]
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
h : a ∉ f.support
hf : f a = 0
hg : g a = 0
⊢ f a = g a
state_after: no goals

tactic: rwa [h₁, not_mem_support_iff] at h
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
ι : Type u_4
M : Type u_5
M' : Type u_6
N : Type u_7
P : Type u_8
G : Type u_9
H : Type u_10
R : Type u_11
S : Type u_12
inst✝ : Zero M
f g : α →₀ M
x✝ : f.support = g.support ∧ ∀ x ∈ f.support, f x = g x
h₁ : f.support = g.support
h₂ : ∀ x ∈ f.support, f x = g x
a : α
h : a ∉ f.support
hf : f a = 0
⊢ g a = 0
state_after: no goals