Definition df-stab 843

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 842	. 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 used by:  stbid  844  stabnot  845  dcstab  856  stdcndc  857  stdcndcOLD  858  stdcn  859  const  864  imanst  900  ddifstab  3361  exmid1stab  4345  fvdifsuppst  6484  suppssrst  6501  suppssrgst  6502  2omotap  7625  bj-trst  16767  bj-fast  16769  bj-nnbist  16772  bj-stim  16774  bj-stan  16775  bj-stand  16776  bj-stal  16777  bj-pm2.18st  16778  bj-con1st  16779  bdstab  16853  subctctexmid  17030  exmidnotnotr  17036