Metamath Proof Explorer


Theorem cgrsub

Description: Removing identical parts from the end of a line segment preserves congruence. Theorem 4.3 of Schwabhauser p. 35. (Contributed by Scott Fenton, 4-Oct-2013)

Ref Expression
Assertion cgrsub NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFABCgrDE

Proof

Step Hyp Ref Expression
1 simprl NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFBBtwnACEBtwnDF
2 simprr NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFACCgrDFBCCgrEF
3 simpl1 NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFN
4 simpl21 NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFA𝔼N
5 simpl31 NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFD𝔼N
6 cgrtriv NA𝔼ND𝔼NAACgrDD
7 3 4 5 6 syl3anc NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFAACgrDD
8 simprrl NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFACCgrDF
9 simpl23 NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFC𝔼N
10 simpl33 NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFF𝔼N
11 cgrcomlr NA𝔼NC𝔼ND𝔼NF𝔼NACCgrDFCACgrFD
12 3 4 9 5 10 11 syl122anc NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFACCgrDFCACgrFD
13 8 12 mpbid NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFCACgrFD
14 7 13 jca NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFAACgrDDCACgrFD
15 simpl22 NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFB𝔼N
16 simpl32 NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFE𝔼N
17 brifs NA𝔼NB𝔼NC𝔼NA𝔼ND𝔼NE𝔼NF𝔼ND𝔼NABCAInnerFiveSegDEFDBBtwnACEBtwnDFACCgrDFBCCgrEFAACgrDDCACgrFD
18 ifscgr NA𝔼NB𝔼NC𝔼NA𝔼ND𝔼NE𝔼NF𝔼ND𝔼NABCAInnerFiveSegDEFDBACgrED
19 17 18 sylbird NA𝔼NB𝔼NC𝔼NA𝔼ND𝔼NE𝔼NF𝔼ND𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFAACgrDDCACgrFDBACgrED
20 3 4 15 9 4 5 16 10 5 19 syl333anc NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFBBtwnACEBtwnDFACCgrDFBCCgrEFAACgrDDCACgrFDBACgrED
21 1 2 14 20 mp3and NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFBACgrED
22 cgrcomlr NB𝔼NA𝔼NE𝔼ND𝔼NBACgrEDABCgrDE
23 3 15 4 16 5 22 syl122anc NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFBACgrEDABCgrDE
24 21 23 mpbid NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFABCgrDE
25 24 ex NA𝔼NB𝔼NC𝔼ND𝔼NE𝔼NF𝔼NBBtwnACEBtwnDFACCgrDFBCCgrEFABCgrDE