Definition df-stab 833

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 832	. 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 105	1 wff (STAB ph <-> ( -. -. ph -> ph ) )

This definition is referenced by:  stbid  834  stabnot  835  dcstab  846  stdcndc  847  stdcndcOLD  848  stdcn  849  const  854  imanst  890  ddifstab  3305  exmid1stab  4252  2omotap  7371  bj-trst  15675  bj-fast  15677  bj-nnbist  15680  bj-stim  15682  bj-stan  15683  bj-stand  15684  bj-stal  15685  bj-pm2.18st  15686  bj-con1st  15687  bdstab  15763  subctctexmid  15937