let p be Prime; :: thesis: ( not p < 67 or p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 or p = 19 or p = 23 or p = 29 or p = 31 or p = 37 or p = 41 or p = 43 or p = 47 or p = 53 or p = 59 or p = 61 )
assume p < 67 ; :: thesis: ( p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 or p = 19 or p = 23 or p = 29 or p = 31 or p = 37 or p = 41 or p = 43 or p = 47 or p = 53 or p = 59 or p = 61 )
then ( 1 + 1 < p + 1 & p < 66 + 1 ) by XREAL_1:6, INT_2:def 4;

per cases then ( ( 2 <= p & p < 61 ) or ( 61 <= p & p <= 61 + 1 ) or ( 62 <= p & p <= 62 + 1 ) or ( 63 <= p & p <= 63 + 1 ) or ( 64 <= p & p <= 64 + 1 ) or ( 65 <= p & p <= 65 + 1 ) ) by NAT_1:13;

suppose ( 2 <= p & p < 61 ) ; :: thesis: ( p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 or p = 19 or p = 23 or p = 29 or p = 31 or p = 37 or p = 41 or p = 43 or p = 47 or p = 53 or p = 59 or p = 61 )

hence ( p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 or p = 19 or p = 23 or p = 29 or p = 31 or p = 37 or p = 41 or p = 43 or p = 47 or p = 53 or p = 59 or p = 61 ) by Ttool61a; :: thesis: verum

end;

suppose ( ( 61 <= p & p <= 61 + 1 ) or ( 62 <= p & p <= 62 + 1 ) or ( 63 <= p & p <= 63 + 1 ) or ( 64 <= p & p <= 64 + 1 ) or ( 65 <= p & p <= 65 + 1 ) ) ; :: thesis: ( p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 or p = 19 or p = 23 or p = 29 or p = 31 or p = 37 or p = 41 or p = 43 or p = 47 or p = 53 or p = 59 or p = 61 )

then p = 61 by XPRIMES0:62, XPRIMES0:63, XPRIMES0:64, XPRIMES0:65, XPRIMES0:66, NAT_1:9;
hence ( p = 2 or p = 3 or p = 5 or p = 7 or p = 11 or p = 13 or p = 17 or p = 19 or p = 23 or p = 29 or p = 31 or p = 37 or p = 41 or p = 43 or p = 47 or p = 53 or p = 59 or p = 61 ) ; :: thesis: verum

end;

end;