Definition df-pi 14642

Description: Define pi = 3.14159..., which is the smallest positive number whose sine is zero. Definition of pi in [Gleason] p. 311. (Contributed by Paul Chapman, 23-Jan-2008.) (Revised by AV, 14-Sep-2020.)

Assertion

Ref	Expression
df-pi	⊢ π = inf((ℝ+ ∩ (◡sin “ {0})), ℝ, < )

Detailed syntax breakdown of Definition df-pi

Step	Hyp	Ref	Expression
1		cpi 14636	. 2 class π
2		crp 11708	. . . 4 class ℝ+
3		csin 14633	. . . . . 6 class sin
4	3	ccnv 5037	. . . . 5 class ◡sin
5		cc0 9815	. . . . . 6 class 0
6	5	csn 4125	. . . . 5 class {0}
7	4, 6	cima 5041	. . . 4 class (◡sin “ {0})
8	2, 7	cin 3539	. . 3 class (ℝ+ ∩ (◡sin “ {0}))
9		cr 9814	. . 3 class ℝ
10		clt 9953	. . 3 class <
11	8, 9, 10	cinf 8230	. 2 class inf((ℝ+ ∩ (◡sin “ {0})), ℝ, < )
12	1, 11	wceq 1475	1 wff π = inf((ℝ+ ∩ (◡sin “ {0})), ℝ, < )

This definition is referenced by:  pilem2  24010  pilem3  24011