Definition df-stab 839

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 838	. 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  840  stabnot  841  dcstab  852  stdcndc  853  stdcndcOLD  854  stdcn  855  const  860  imanst  896  ddifstab  3351  exmid1stab  4321  fvdifsuppst  6444  suppssrst  6461  suppssrgst  6462  2omotap  7573  bj-trst  16511  bj-fast  16513  bj-nnbist  16516  bj-stim  16518  bj-stan  16519  bj-stand  16520  bj-stal  16521  bj-pm2.18st  16522  bj-con1st  16523  bdstab  16597  subctctexmid  16774  exmidnotnotr  16779