Definition df-stab 816

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 815	. 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  817  stabnot  818  dcstab  829  stdcndc  830  stdcndcOLD  831  stdcn  832  const  837  imanst  873  ddifstab  3208  cnstab  8407  bj-trst  12951  bj-fast  12952  bj-nnbist  12953  bj-stim  12954  bj-stan  12955  bj-stand  12956  bj-stal  12957  bj-pm2.18st  12958  bdstab  13025  exmid1stab  13195  subctctexmid  13196