:: DIRAF  semantic presentation
definition
let c1 be  non 
empty  set ;
let c2 be   
Relation of 
[:c1,c1:];
func  lambda c2 ->   Relation of 
[:a1,a1:] means :
Def1: 
:: DIRAF:def 1
for 
b1, 
b2, 
b3, 
b4 being   
Element of 
a1 holds 
 ( 
[[b1,b2],[b3,b4]] in a3 iff ( 
[[b1,b2],[b3,b4]] in a2 or 
[[b1,b2],[b4,b3]] in a2 ) );
existence 
ex b1 being  Relation of [:c1,c1:] st 
for b2, b3, b4, b5 being   Element of c1 holds 
 ( [[b2,b3],[b4,b5]] in b1 iff ( [[b2,b3],[b4,b5]] in c2 or [[b2,b3],[b5,b4]] in c2 ) )
 
uniqueness 
for b1, b2 being  Relation of [:c1,c1:]  st ( for b3, b4, b5, b6 being   Element of c1 holds 
 ( [[b3,b4],[b5,b6]] in b1 iff ( [[b3,b4],[b5,b6]] in c2 or [[b3,b4],[b6,b5]] in c2 ) ) ) & ( for b3, b4, b5, b6 being   Element of c1 holds 
 ( [[b3,b4],[b5,b6]] in b2 iff ( [[b3,b4],[b5,b6]] in c2 or [[b3,b4],[b6,b5]] in c2 ) ) ) holds 
b1 = b2
 
 
end;
 
:: deftheorem Def1   defines lambda DIRAF:def 1 : 
for 
b1 being non 
empty  set  for 
b2, 
b3 being  
Relation of 
[:b1,b1:] holds 
 ( 
b3 =  lambda b2 iff for 
b4, 
b5, 
b6, 
b7 being   
Element of 
b1 holds 
 ( 
[[b4,b5],[b6,b7]] in b3 iff ( 
[[b4,b5],[b6,b7]] in b2 or 
[[b4,b5],[b7,b6]] in b2 ) ) );
:: deftheorem Def2   defines Lambda DIRAF:def 2 : 
theorem Th1: :: DIRAF:1
canceled; 
theorem Th2: :: DIRAF:2
canceled; 
theorem Th3: :: DIRAF:3
canceled; 
theorem Th4: :: DIRAF:4
Lemma3: 
for b1 being  OAffinSpace
 for b2, b3, b4, b5 being  Element of b1  st b2,b3 // b4,b5 holds 
b4,b5 // b2,b3
 
theorem Th5: :: DIRAF:5
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b2,
b3 // b4,
b5 holds 
( 
b3,
b2 // b5,
b4 & 
b4,
b5 // b2,
b3 & 
b5,
b4 // b3,
b2 )
theorem Th6: :: DIRAF:6
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5, 
b6, 
b7 being  
Element of 
b1  st 
b2 <> b3 & 
b4,
b5 // b2,
b3 & 
b2,
b3 // b6,
b7 holds 
b4,
b5 // b6,
b7
theorem Th7: :: DIRAF:7
theorem Th8: :: DIRAF:8
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b2,
b3 // b4,
b5 & 
b2,
b3 // b5,
b4 & not 
b2 = b3 holds 
b4 = b5
theorem Th9: :: DIRAF:9
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4 being  
Element of 
b1 holds 
 ( 
b2,
b3 // b2,
b4 iff ( 
b2,
b3 // b3,
b4 or 
b2,
b4 // b4,
b3 ) )
:: deftheorem Def3   defines Mid DIRAF:def 3 : 
theorem Th10: :: DIRAF:10
canceled; 
theorem Th11: :: DIRAF:11
theorem Th12: :: DIRAF:12
theorem Th13: :: DIRAF:13
theorem Th14: :: DIRAF:14
theorem Th15: :: DIRAF:15
theorem Th16: :: DIRAF:16
theorem Th17: :: DIRAF:17
theorem Th18: :: DIRAF:18
theorem Th19: :: DIRAF:19
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b2 <> b3 &  
Mid b2,
b3,
b4 &  
Mid b2,
b3,
b5 & not  
Mid b3,
b4,
b5 holds  
Mid b3,
b5,
b4
theorem Th20: :: DIRAF:20
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b2 <> b3 &  
Mid b2,
b3,
b4 &  
Mid b2,
b3,
b5 & not  
Mid b2,
b4,
b5 holds  
Mid b2,
b5,
b4
theorem Th21: :: DIRAF:21
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st  
Mid b2,
b3,
b4 &  
Mid b2,
b5,
b4 & not  
Mid b2,
b3,
b5 holds  
Mid b2,
b5,
b3
:: deftheorem Def4   defines '||' DIRAF:def 4 : 
theorem Th22: :: DIRAF:22
canceled; 
theorem Th23: :: DIRAF:23
theorem Th24: :: DIRAF:24
theorem Th25: :: DIRAF:25
Lemma16: 
for b1 being  OAffinSpace
 for b2, b3, b4, b5, b6, b7 being  Element of b1  st b2 <> b3 & b2,b3 '||' b4,b5 & b2,b3 '||' b6,b7 holds 
b4,b5 '||' b6,b7
 
theorem Th26: :: DIRAF:26
theorem Th27: :: DIRAF:27
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b2,
b3 '||' b4,
b5 holds 
( 
b2,
b3 '||' b5,
b4 & 
b3,
b2 '||' b4,
b5 & 
b3,
b2 '||' b5,
b4 & 
b4,
b5 '||' b2,
b3 & 
b4,
b5 '||' b3,
b2 & 
b5,
b4 '||' b2,
b3 & 
b5,
b4 '||' b3,
b2 )
theorem Th28: :: DIRAF:28
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5, 
b6, 
b7 being  
Element of 
b1  st 
b2 <> b3 & ( ( 
b2,
b3 '||' b4,
b5 & 
b2,
b3 '||' b6,
b7 ) or ( 
b2,
b3 '||' b4,
b5 & 
b6,
b7 '||' b2,
b3 ) or ( 
b4,
b5 '||' b2,
b3 & 
b6,
b7 '||' b2,
b3 ) or ( 
b4,
b5 '||' b2,
b3 & 
b2,
b3 '||' b6,
b7 ) ) holds 
b4,
b5 '||' b6,
b7
theorem Th29: :: DIRAF:29
theorem Th30: :: DIRAF:30
theorem Th31: :: DIRAF:31
theorem Th32: :: DIRAF:32
:: deftheorem Def5   defines LIN DIRAF:def 5 : 
theorem Th33: :: DIRAF:33
canceled; 
theorem Th34: :: DIRAF:34
theorem Th35: :: DIRAF:35
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4 being  
Element of 
b1  holds 
(  not 
b2,
b3,
b4 is_collinear  or  
Mid b2,
b3,
b4 or  
Mid b3,
b2,
b4 or  
Mid b2,
b4,
b3 )
Lemma25: 
for b1 being  OAffinSpace
 for b2, b3, b4 being  Element of b1  st b2,b3,b4 is_collinear  holds 
( b2,b4,b3 is_collinear  & b3,b2,b4 is_collinear  )
 
theorem Th36: :: DIRAF:36
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4 being  
Element of 
b1  st 
b2,
b3,
b4 is_collinear  holds 
( 
b2,
b4,
b3 is_collinear  & 
b3,
b2,
b4 is_collinear  & 
b3,
b4,
b2 is_collinear  & 
b4,
b2,
b3 is_collinear  & 
b4,
b3,
b2 is_collinear  )
theorem Th37: :: DIRAF:37
theorem Th38: :: DIRAF:38
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5, 
b6 being  
Element of 
b1  st 
b2 <> b3 & 
b2,
b3,
b4 is_collinear  & 
b2,
b3,
b5 is_collinear  & 
b2,
b3,
b6 is_collinear  holds 
b4,
b5,
b6 is_collinear 
theorem Th39: :: DIRAF:39
theorem Th40: :: DIRAF:40
theorem Th41: :: DIRAF:41
for 
b1 being  
OAffinSpace for 
b2, 
b3, 
b4, 
b5, 
b6 being  
Element of 
b1  st 
b2 <> b3 & 
b4,
b5,
b2 is_collinear  & 
b4,
b5,
b3 is_collinear  & 
b2,
b3,
b6 is_collinear  holds 
b4,
b5,
b6 is_collinear 
theorem Th42: :: DIRAF:42
theorem Th43: :: DIRAF:43
theorem Th44: :: DIRAF:44
canceled; 
theorem Th45: :: DIRAF:45
for 
b1 being  
OAffinSpace for 
b2 being non 
empty  AffinStruct   st 
b2 =  Lambda b1 holds 
for 
b3, 
b4, 
b5, 
b6 being  
Element of 
b1 for 
b7, 
b8, 
b9, 
b10 being  
Element of 
b2  st 
b3 = b7 & 
b4 = b8 & 
b5 = b9 & 
b6 = b10 holds 
( 
b7,
b8 // b9,
b10 iff 
b3,
b4 '||' b5,
b6 )
theorem Th46: :: DIRAF:46
for 
b1 being  
OAffinSpace for 
b2 being non 
empty  AffinStruct   st 
b2 =  Lambda b1 holds 
( ex 
b3, 
b4 being  
Element of 
b2 st 
b3 <> b4 & ( for 
b3, 
b4, 
b5, 
b6, 
b7, 
b8 being  
Element of 
b2 holds 
 ( 
b3,
b4 // b4,
b3 & 
b3,
b4 // b5,
b5 & ( 
b3 <> b4 & 
b3,
b4 // b5,
b6 & 
b3,
b4 // b7,
b8 implies 
b5,
b6 // b7,
b8 ) & ( 
b3,
b4 // b3,
b5 implies 
b4,
b3 // b4,
b5 ) ) ) & not for 
b3, 
b4, 
b5 being  
Element of 
b2 holds  
b3,
b4 // b3,
b5 & ( for 
b3, 
b4, 
b5 being  
Element of 
b2 ex 
b6 being  
Element of 
b2 st 
( 
b3,
b5 // b4,
b6 & 
b4 <> b6 ) ) & ( for 
b3, 
b4, 
b5 being  
Element of 
b2 ex 
b6 being  
Element of 
b2 st 
( 
b3,
b4 // b5,
b6 & 
b3,
b5 // b4,
b6 ) ) & ( for 
b3, 
b4, 
b5, 
b6 being  
Element of 
b2  st 
b5,
b3 // b3,
b6 & 
b3 <> b5 holds 
ex 
b7 being  
Element of 
b2 st 
( 
b4,
b3 // b3,
b7 & 
b4,
b5 // b6,
b7 ) ) )
definition
let c1 be  non 
empty  AffinStruct ;
canceled;attr a1 is 
AffinSpace-like means :
Def7: 
:: DIRAF:def 7
( ( for 
b1, 
b2, 
b3, 
b4, 
b5, 
b6 being  
Element of 
a1 holds 
 ( 
b1,
b2 // b2,
b1 & 
b1,
b2 // b3,
b3 & ( 
b1 <> b2 & 
b1,
b2 // b3,
b4 & 
b1,
b2 // b5,
b6 implies 
b3,
b4 // b5,
b6 ) & ( 
b1,
b2 // b1,
b3 implies 
b2,
b1 // b2,
b3 ) ) ) & not for 
b1, 
b2, 
b3 being  
Element of 
a1 holds  
b1,
b2 // b1,
b3 & ( for 
b1, 
b2, 
b3 being  
Element of 
a1 ex 
b4 being  
Element of 
a1 st 
( 
b1,
b3 // b2,
b4 & 
b2 <> b4 ) ) & ( for 
b1, 
b2, 
b3 being  
Element of 
a1 ex 
b4 being  
Element of 
a1 st 
( 
b1,
b2 // b3,
b4 & 
b1,
b3 // b2,
b4 ) ) & ( for 
b1, 
b2, 
b3, 
b4 being  
Element of 
a1  st 
b3,
b1 // b1,
b4 & 
b1 <> b3 holds 
ex 
b5 being  
Element of 
a1 st 
( 
b2,
b1 // b1,
b5 & 
b2,
b3 // b4,
b5 ) ) );
 
end;
 
:: deftheorem Def6  DIRAF:def 6 : 
canceled; 
:: deftheorem Def7   defines AffinSpace-like DIRAF:def 7 : 
for 
b1 being non 
empty  AffinStruct  holds 
 ( 
b1 is 
AffinSpace-like iff ( ( for 
b2, 
b3, 
b4, 
b5, 
b6, 
b7 being  
Element of 
b1 holds 
 ( 
b2,
b3 // b3,
b2 & 
b2,
b3 // b4,
b4 & ( 
b2 <> b3 & 
b2,
b3 // b4,
b5 & 
b2,
b3 // b6,
b7 implies 
b4,
b5 // b6,
b7 ) & ( 
b2,
b3 // b2,
b4 implies 
b3,
b2 // b3,
b4 ) ) ) & not for 
b2, 
b3, 
b4 being  
Element of 
b1 holds  
b2,
b3 // b2,
b4 & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b4 // b3,
b5 & 
b3 <> b5 ) ) & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b3 // b4,
b5 & 
b2,
b4 // b3,
b5 ) ) & ( for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b4,
b2 // b2,
b5 & 
b2 <> b4 holds 
ex 
b6 being  
Element of 
b1 st 
( 
b3,
b2 // b2,
b6 & 
b3,
b4 // b5,
b6 ) ) ) );
theorem Th47: :: DIRAF:47
for 
b1 being  
AffinSpace holds 
 ( ex 
b2, 
b3 being  
Element of 
b1 st 
b2 <> b3 & ( for 
b2, 
b3, 
b4, 
b5, 
b6, 
b7 being  
Element of 
b1 holds 
 ( 
b2,
b3 // b3,
b2 & 
b2,
b3 // b4,
b4 & ( 
b2 <> b3 & 
b2,
b3 // b4,
b5 & 
b2,
b3 // b6,
b7 implies 
b4,
b5 // b6,
b7 ) & ( 
b2,
b3 // b2,
b4 implies 
b3,
b2 // b3,
b4 ) ) ) & not for 
b2, 
b3, 
b4 being  
Element of 
b1 holds  
b2,
b3 // b2,
b4 & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b4 // b3,
b5 & 
b3 <> b5 ) ) & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b3 // b4,
b5 & 
b2,
b4 // b3,
b5 ) ) & ( for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b4,
b2 // b2,
b5 & 
b2 <> b4 holds 
ex 
b6 being  
Element of 
b1 st 
( 
b3,
b2 // b2,
b6 & 
b3,
b4 // b5,
b6 ) ) ) 
by Def7, REALSET2:def 7;
theorem Th48: :: DIRAF:48
theorem Th49: :: DIRAF:49
for 
b1 being non 
empty  AffinStruct  holds 
 ( ( ex 
b2, 
b3 being  
Element of 
b1 st 
b2 <> b3 & ( for 
b2, 
b3, 
b4, 
b5, 
b6, 
b7 being  
Element of 
b1 holds 
 ( 
b2,
b3 // b3,
b2 & 
b2,
b3 // b4,
b4 & ( 
b2 <> b3 & 
b2,
b3 // b4,
b5 & 
b2,
b3 // b6,
b7 implies 
b4,
b5 // b6,
b7 ) & ( 
b2,
b3 // b2,
b4 implies 
b3,
b2 // b3,
b4 ) ) ) & not for 
b2, 
b3, 
b4 being  
Element of 
b1 holds  
b2,
b3 // b2,
b4 & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b4 // b3,
b5 & 
b3 <> b5 ) ) & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b3 // b4,
b5 & 
b2,
b4 // b3,
b5 ) ) & ( for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b4,
b2 // b2,
b5 & 
b2 <> b4 holds 
ex 
b6 being  
Element of 
b1 st 
( 
b3,
b2 // b2,
b6 & 
b3,
b4 // b5,
b6 ) ) ) iff 
b1 is   
AffinSpace ) 
by Def7, REALSET2:def 7;
theorem Th50: :: DIRAF:50
theorem Th51: :: DIRAF:51
:: deftheorem Def8   defines 2-dimensional DIRAF:def 8 : 
theorem Th52: :: DIRAF:52
canceled; 
theorem Th53: :: DIRAF:53
theorem Th54: :: DIRAF:54
for 
b1 being non 
empty  AffinStruct  holds 
 ( 
b1 is   
AffinPlane iff ( ex 
b2, 
b3 being  
Element of 
b1 st 
b2 <> b3 & ( for 
b2, 
b3, 
b4, 
b5, 
b6, 
b7 being  
Element of 
b1 holds 
 ( 
b2,
b3 // b3,
b2 & 
b2,
b3 // b4,
b4 & ( 
b2 <> b3 & 
b2,
b3 // b4,
b5 & 
b2,
b3 // b6,
b7 implies 
b4,
b5 // b6,
b7 ) & ( 
b2,
b3 // b2,
b4 implies 
b3,
b2 // b3,
b4 ) ) ) & not for 
b2, 
b3, 
b4 being  
Element of 
b1 holds  
b2,
b3 // b2,
b4 & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b4 // b3,
b5 & 
b3 <> b5 ) ) & ( for 
b2, 
b3, 
b4 being  
Element of 
b1 ex 
b5 being  
Element of 
b1 st 
( 
b2,
b3 // b4,
b5 & 
b2,
b4 // b3,
b5 ) ) & ( for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st 
b4,
b2 // b2,
b5 & 
b2 <> b4 holds 
ex 
b6 being  
Element of 
b1 st 
( 
b3,
b2 // b2,
b6 & 
b3,
b4 // b5,
b6 ) ) & ( for 
b2, 
b3, 
b4, 
b5 being  
Element of 
b1  st not 
b2,
b3 // b4,
b5 holds 
ex 
b6 being  
Element of 
b1 st 
( 
b2,
b3 // b2,
b6 & 
b4,
b5 // b4,
b6 ) ) ) ) 
by Def7, Def8, REALSET2:def 7;