1 let line_INDUCT,line_RECURSION = define_type
2 "line = Line_1 | Line_2 | Line_3 | Line_4 |
3 Line_5 | Line_6 | Line_7";;
5 let point_INDUCT,point_RECURSION = define_type
6 "point = Point_1 | Point_2 | Point_3 | Point_4 |
7 Point_5 | Point_6 | Point_7";;
10 [1,1; 1,2; 1,3; 2,1; 2,4; 2,5; 3,1; 3,6; 3,7; 4,2; 4,4;
11 4,6; 5,2; 5,5; 5,7; 6,3; 6,4; 6,7; 7,3; 7,5; 7,6];;
13 let fano_point i = mk_const("Point_"^string_of_int i,[]);;
14 let fano_line i = mk_const("Line_"^string_of_int i,[]);;
15 let p = `p:point` and l = `l:line` ;;
17 let fano_clause (i,j) = mk_conj(mk_eq(p,fano_point i),mk_eq(l,fano_line j));;
19 parse_as_infix("ON",(11,"right"));;
21 let ON = new_definition
22 (mk_eq(`((ON):point->line->bool) p l`,
23 list_mk_disj(map fano_clause fano_incidence)));;
25 let ON_CLAUSES = prove
26 (list_mk_conj(allpairs
27 (fun i j -> mk_eq(mk_comb(mk_comb(`(ON)`,fano_point i),fano_line j),
28 if mem (i,j) fano_incidence then `T` else `F`))
30 REWRITE_TAC[ON; distinctness "line"; distinctness "point"]);;
32 let FORALL_POINT = prove
33 (`(!p. P p) <=> P Point_1 /\ P Point_2 /\ P Point_3 /\ P Point_4 /\
34 P Point_5 /\ P Point_6 /\ P Point_7`,
35 EQ_TAC THENL [SIMP_TAC[]; REWRITE_TAC[point_INDUCT]]);;
37 let FORALL_LINE = prove
38 (`(!p. P p) <=> P Line_1 /\ P Line_2 /\ P Line_3 /\ P Line_4 /\
39 P Line_5 /\ P Line_6 /\ P Line_7`,
40 EQ_TAC THENL [SIMP_TAC[]; REWRITE_TAC[line_INDUCT]]);;
42 let EXISTS_POINT = prove
43 (`(?p. P p) <=> P Point_1 \/ P Point_2 \/ P Point_3 \/ P Point_4 \/
44 P Point_5 \/ P Point_6 \/ P Point_7`,
45 MATCH_MP_TAC(TAUT `(~p <=> ~q) ==> (p <=> q)`) THEN
46 REWRITE_TAC[DE_MORGAN_THM; NOT_EXISTS_THM; FORALL_POINT]);;
48 let EXISTS_LINE = prove
49 (`(?p. P p) <=> P Line_1 \/ P Line_2 \/ P Line_3 \/ P Line_4 \/
50 P Line_5 \/ P Line_6 \/ P Line_7`,
51 MATCH_MP_TAC(TAUT `(~p <=> ~q) ==> (p <=> q)`) THEN
52 REWRITE_TAC[DE_MORGAN_THM; NOT_EXISTS_THM; FORALL_LINE]);;
55 GEN_REWRITE_TAC DEPTH_CONV
56 [FORALL_POINT; EXISTS_LINE; EXISTS_POINT; FORALL_LINE] THEN
57 GEN_REWRITE_TAC DEPTH_CONV
59 [ON_CLAUSES; distinctness "point"; distinctness "line"]);;
61 let FANO_RULE tm = prove(tm,FANO_TAC);;
63 let AXIOM_1 = FANO_RULE
64 `!p p'. ~(p = p') ==> ?l. p ON l /\ p' ON l /\
65 !l'. p ON l' /\ p' ON l' ==> l' = l`;;
67 let AXIOM_2 = FANO_RULE
68 `!l l'. ?p. p ON l /\ p ON l'`;;
70 let AXIOM_3 = FANO_RULE
71 `?p p' p''. ~(p = p') /\ ~(p' = p'') /\ ~(p = p'') /\
72 ~(?l. p ON l /\ p' ON l /\ p'' ON l)`;;
74 let AXIOM_4 = FANO_RULE
75 `!l. ?p p' p''. ~(p = p') /\ ~(p' = p'') /\ ~(p = p'') /\
76 p ON l /\ p' ON l /\ p'' ON l`;;