Definition df-fmla 35377

Description: Define the predicate which defines the set of valid Godel formulas. The parameter 𝑛 defines the maximum height of the formulas: the set (Fmla‘∅) is all formulas of the form 𝑥 ∈ 𝑦 (which in our coding scheme is the set ({∅} × (ω × ω)); see df-sat 35375 for the full coding scheme), see fmla0 35414, and each extra level adds to the complexity of the formulas in (Fmla‘𝑛), see fmlasuc 35418. Remark: it is sufficient to have atomic formulas of the form 𝑥 ∈ 𝑦 only, because equations (formulas of the form 𝑥 = 𝑦), which are required as (atomic) formulas, can be introduced as a defined notion in terms of ∈_𝑔, see df-goeq 35476. (Fmla‘ω) = ∪ 𝑛 ∈ ω(Fmla‘𝑛) is the set of all valid formulas, see fmla 35413. (Contributed by Mario Carneiro, 14-Jul-2013.)

Assertion

Ref	Expression
df-fmla	⊢ Fmla = (𝑛 ∈ suc ω ↦ dom ((∅ Sat ∅)‘𝑛))

Detailed syntax breakdown of Definition df-fmla

Step	Hyp	Ref	Expression
1		cfmla 35369	. 2 class Fmla
2		vn	. . 3 setvar 𝑛
3		com 7796	. . . 4 class ω
4	3	csuc 6308	. . 3 class suc ω
5	2	cv 1540	. . . . 5 class 𝑛
6		c0 4283	. . . . . 6 class ∅
7		csat 35368	. . . . . 6 class Sat
8	6, 6, 7	co 7346	. . . . 5 class (∅ Sat ∅)
9	5, 8	cfv 6481	. . . 4 class ((∅ Sat ∅)‘𝑛)
10	9	cdm 5616	. . 3 class dom ((∅ Sat ∅)‘𝑛)
11	2, 4, 10	cmpt 5172	. 2 class (𝑛 ∈ suc ω ↦ dom ((∅ Sat ∅)‘𝑛))
12	1, 11	wceq 1541	1 wff Fmla = (𝑛 ∈ suc ω ↦ dom ((∅ Sat ∅)‘𝑛))

This definition is referenced by:  fmlafv  35412  fmla  35413  fmlasuc0  35416