lemma csx_feqg_conf (S):
reflexive … S → symmetric … S →
- â\88\80G1,L1,T1. â\9dªG1,L1â\9d« ⊢ ⬈*𝐒 T1 →
- â\88\80G2,L2,T2. â\9dªG1,L1,T1â\9d« â\89\9b[S] â\9dªG2,L2,T2â\9d« â\86\92 â\9dªG2,L2â\9d« ⊢ ⬈*𝐒 T2.
+ â\88\80G1,L1,T1. â\9d¨G1,L1â\9d© ⊢ ⬈*𝐒 T1 →
+ â\88\80G2,L2,T2. â\9d¨G1,L1,T1â\9d© â\89\9b[S] â\9d¨G2,L2,T2â\9d© â\86\92 â\9d¨G2,L2â\9d© ⊢ ⬈*𝐒 T2.
#S #H1S #H2S #G1 #L1 #T1 #HT1 #G2 #L2 #T2 * -G2 -L2 -T2
/3 width=6 by csx_reqg_conf, csx_teqg_trans/
qed-.