Theorem sadcl

Description: The sum of two sequences is a sequence. (Contributed by Mario Carneiro, 5-Sep-2016)

	Ref	Expression
Assertion	sadcl	⊢ ( ( 𝐴 ⊆ ℕ0 ∧ 𝐵 ⊆ ℕ0 ) → ( 𝐴 sadd 𝐵 ) ⊆ ℕ0 )

Proof

Step	Hyp	Ref	Expression
1		simpl	⊢ ( ( 𝐴 ⊆ ℕ0 ∧ 𝐵 ⊆ ℕ0 ) → 𝐴 ⊆ ℕ0 )
2		simpr	⊢ ( ( 𝐴 ⊆ ℕ0 ∧ 𝐵 ⊆ ℕ0 ) → 𝐵 ⊆ ℕ0 )
3		eqid	⊢ seq 0 ( ( 𝑐 ∈ 2o , 𝑚 ∈ ℕ0 ↦ if ( cadd ( 𝑚 ∈ 𝐴 , 𝑚 ∈ 𝐵 , ∅ ∈ 𝑐 ) , 1o , ∅ ) ) , ( 𝑛 ∈ ℕ0 ↦ if ( 𝑛 = 0 , ∅ , ( 𝑛 − 1 ) ) ) ) = seq 0 ( ( 𝑐 ∈ 2o , 𝑚 ∈ ℕ0 ↦ if ( cadd ( 𝑚 ∈ 𝐴 , 𝑚 ∈ 𝐵 , ∅ ∈ 𝑐 ) , 1o , ∅ ) ) , ( 𝑛 ∈ ℕ0 ↦ if ( 𝑛 = 0 , ∅ , ( 𝑛 − 1 ) ) ) )
4	1 2 3	sadfval	⊢ ( ( 𝐴 ⊆ ℕ0 ∧ 𝐵 ⊆ ℕ0 ) → ( 𝐴 sadd 𝐵 ) = { 𝑘 ∈ ℕ0 ∣ hadd ( 𝑘 ∈ 𝐴 , 𝑘 ∈ 𝐵 , ∅ ∈ ( seq 0 ( ( 𝑐 ∈ 2o , 𝑚 ∈ ℕ0 ↦ if ( cadd ( 𝑚 ∈ 𝐴 , 𝑚 ∈ 𝐵 , ∅ ∈ 𝑐 ) , 1o , ∅ ) ) , ( 𝑛 ∈ ℕ0 ↦ if ( 𝑛 = 0 , ∅ , ( 𝑛 − 1 ) ) ) ) ‘ 𝑘 ) ) } )
5		ssrab2	⊢ { 𝑘 ∈ ℕ0 ∣ hadd ( 𝑘 ∈ 𝐴 , 𝑘 ∈ 𝐵 , ∅ ∈ ( seq 0 ( ( 𝑐 ∈ 2o , 𝑚 ∈ ℕ0 ↦ if ( cadd ( 𝑚 ∈ 𝐴 , 𝑚 ∈ 𝐵 , ∅ ∈ 𝑐 ) , 1o , ∅ ) ) , ( 𝑛 ∈ ℕ0 ↦ if ( 𝑛 = 0 , ∅ , ( 𝑛 − 1 ) ) ) ) ‘ 𝑘 ) ) } ⊆ ℕ0
6	4 5	eqsstrdi	⊢ ( ( 𝐴 ⊆ ℕ0 ∧ 𝐵 ⊆ ℕ0 ) → ( 𝐴 sadd 𝐵 ) ⊆ ℕ0 )