-- Mathlib/RingTheory/Algebraic/Integral.lean
theorem _root_.IsIntegral.trans_isAlgebraic [alg : Algebra.IsAlgebraic R S]
    {a : A} (h : IsIntegral S a) : IsAlgebraic R a

Proof state:
case inr
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Nontrivial A
⊢ IsAlgebraic R a

Tactic:
have := Module.nontrivial S A

Result:
case inr
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Nontrivial A
this : Nontrivial S
⊢ IsAlgebraic R a

Proof state:
case inl
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Subsingleton A
this : Nontrivial R
⊢ IsAlgebraic R a

Tactic:
exact Subsingleton.elim a 0 ▸ isAlgebraic_zero

Result:
no goals

Proof state:
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
⊢ IsAlgebraic R a

Tactic:
cases subsingleton_or_nontrivial A

Result:
case inl
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Subsingleton A
⊢ IsAlgebraic R a

case inr
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Nontrivial A
⊢ IsAlgebraic R a

Proof state:
case inr
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Nontrivial A
this : Nontrivial S
⊢ IsAlgebraic R a

Tactic:
exact h.isAlgebraic.restrictScalars _

Result:
no goals

Proof state:
case inl
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Subsingleton A
⊢ IsAlgebraic R a

Tactic:
have := Algebra.IsAlgebraic.nontrivial R S

Result:
case inl
R : Type u_1
S : Type u_2
A : Type u_3
inst✝⁷ : CommRing R
inst✝⁶ : CommRing S
inst✝⁵ : Ring A
inst✝⁴ : Algebra R S
inst✝³ : Algebra R A
inst✝² : Algebra S A
inst✝¹ : IsScalarTower R S A
inst✝ : NoZeroDivisors S
alg : Algebra.IsAlgebraic R S
a : A
h : IsIntegral S a
h✝ : Subsingleton A
this : Nontrivial R
⊢ IsAlgebraic R a