Definition df-stab 821

Description: Propositions where a double-negative can be removed are called stable. See Chapter 2 [Moschovakis] p. 2.

Our notation for stability is a connective STAB which we place before the formula in question. For example, STAB x = y corresponds to " x = y is stable".

(Contributed by David A. Wheeler, 13-Aug-2018.)

Assertion

Ref	Expression
df-stab	|- (STAB ph <-> ( -. -. ph -> ph ) )

Detailed syntax breakdown of Definition df-stab

Step	Hyp	Ref	Expression
1		wph	. . 3 wff ph
2	1	wstab 820	. 2 wff STAB ph
3	1	wn 3	. . . 4 wff -. ph
4	3	wn 3	. . 3 wff -. -. ph
5	4, 1	wi 4	. 2 wff ( -. -. ph -> ph )
6	2, 5	wb 104	1 wff (STAB ph <-> ( -. -. ph -> ph ) )

This definition is referenced by:  stbid  822  stabnot  823  dcstab  834  stdcndc  835  stdcndcOLD  836  stdcn  837  const  842  imanst  878  ddifstab  3254  bj-trst  13620  bj-fast  13622  bj-nnbist  13625  bj-stim  13627  bj-stan  13628  bj-stand  13629  bj-stal  13630  bj-pm2.18st  13631  bj-con1st  13632  bdstab  13709  exmid1stab  13880  subctctexmid  13881