Theorem isgbo

Description: The predicate "is an odd Goldbach number". An odd Goldbach number is an odd integer having a Goldbach partition, i.e. which can be written as sum of three odd primes. (Contributed by AV, 26-Jul-2020)

	Ref	Expression
Assertion	isgbo	⊢ ( 𝑍 ∈ GoldbachOdd ↔ ( 𝑍 ∈ Odd ∧ ∃ 𝑝 ∈ ℙ ∃ 𝑞 ∈ ℙ ∃ 𝑟 ∈ ℙ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑍 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ) )

Proof

Step	Hyp	Ref	Expression
1		eqeq1	⊢ ( 𝑧 = 𝑍 → ( 𝑧 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ↔ 𝑍 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) )
2	1	anbi2d	⊢ ( 𝑧 = 𝑍 → ( ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑧 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ↔ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑍 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ) )
3	2	rexbidv	⊢ ( 𝑧 = 𝑍 → ( ∃ 𝑟 ∈ ℙ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑧 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ↔ ∃ 𝑟 ∈ ℙ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑍 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ) )
4	3	2rexbidv	⊢ ( 𝑧 = 𝑍 → ( ∃ 𝑝 ∈ ℙ ∃ 𝑞 ∈ ℙ ∃ 𝑟 ∈ ℙ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑧 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ↔ ∃ 𝑝 ∈ ℙ ∃ 𝑞 ∈ ℙ ∃ 𝑟 ∈ ℙ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑍 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ) )
5		df-gbo	⊢ GoldbachOdd = { 𝑧 ∈ Odd ∣ ∃ 𝑝 ∈ ℙ ∃ 𝑞 ∈ ℙ ∃ 𝑟 ∈ ℙ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑧 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) }
6	4 5	elrab2	⊢ ( 𝑍 ∈ GoldbachOdd ↔ ( 𝑍 ∈ Odd ∧ ∃ 𝑝 ∈ ℙ ∃ 𝑞 ∈ ℙ ∃ 𝑟 ∈ ℙ ( ( 𝑝 ∈ Odd ∧ 𝑞 ∈ Odd ∧ 𝑟 ∈ Odd ) ∧ 𝑍 = ( ( 𝑝 + 𝑞 ) + 𝑟 ) ) ) )