TPTP Problem File: SEV442^1.p
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% File : SEV442^1 : TPTP v9.0.0. Released v7.0.0.
% Domain : Set Theory (Combinatorics, finite sets)
% Problem : International Mathematical Olympiad, 1994, Problem 1
% Version : [Mat16] axioms : Especial.
% English : Let m and n be positive integers. Let a_1, a_2, ..., a_m be
% distinct elements of \{1, 2, ... , n\} such that whenever a_i +
% a_j =< n for some i, j, 1 =< i =< j =< m, there exists k, 1
% =< k =< m, with a_i + a_j = a_k. Prove that \a_1 + a_2
% + ... + a_m/m >= (n+1)/2.
% Refs : [Mat16] Matsuzaki (2016), Email to Geoff Sutcliffe
% : [MI+16] Matsuzaki et al. (2016), Race against the Teens - Benc
% Source : [Mat16]
% Names : IMO-1994-1.p [Mat16]
% Status : Theorem
% Rating : ? v7.0.0
% Syntax : Number of formulae : 3485 ( 728 unt;1199 typ; 0 def)
% Number of atoms : 6449 (2211 equ; 0 cnn)
% Maximal formula atoms : 24 ( 2 avg)
% Number of connectives : 39706 ( 105 ~; 233 |;1186 &;36052 @)
% (1095 <=>;1035 =>; 0 <=; 0 <~>)
% Maximal formula depth : 33 ( 8 avg)
% Number arithmetic : 4521 ( 387 atm;1221 fun; 969 num;1944 var)
% Number of types : 40 ( 36 usr; 3 ari)
% Number of type conns : 2408 (2408 >; 0 *; 0 +; 0 <<)
% Number of symbols : 1210 (1167 usr; 64 con; 0-9 aty)
% Number of variables : 8064 ( 405 ^;7093 !; 430 ?;8064 :)
% ( 136 !>; 0 ?*; 0 @-; 0 @+)
% SPC : TH1_THM_EQU_ARI
% Comments : Theory: PA; Score: 7; Author: Jumma Kudo;
% Generated: 2014-11-11
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include('Axioms/MAT001^0.ax').
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thf(p,conjecture,
! [V_n: $int,V_m: $int,V_an: 'ListOf' @ $int] :
( ( ( $greater @ V_m @ 0 )
& ( $greater @ V_n @ 0 )
& ( ( 'list-len/1' @ $int @ V_an )
= V_m )
& ! [V_i_dot_1: $int] :
( ( ( $lesseq @ 1 @ V_i_dot_1 )
& ( $lesseq @ V_i_dot_1 @ V_m ) )
=> ( ( $lesseq @ 1 @ ( 'nth/2' @ $int @ ( $difference @ V_i_dot_1 @ 1 ) @ V_an ) )
& ( $lesseq @ ( 'nth/2' @ $int @ ( $difference @ V_i_dot_1 @ 1 ) @ V_an ) @ V_n ) ) )
& ! [V_i_dot_0: $int,V_j_dot_0: $int] :
( ( ( $lesseq @ 1 @ V_i_dot_0 )
& ( $less @ V_i_dot_0 @ V_j_dot_0 )
& ( $lesseq @ V_j_dot_0 @ V_m ) )
=> ( ( 'nth/2' @ $int @ ( $difference @ V_i_dot_0 @ 1 ) @ V_an )
!= ( 'nth/2' @ $int @ ( $difference @ V_j_dot_0 @ 1 ) @ V_an ) ) )
& ! [V_i: $int,V_j: $int] :
( ( ( $lesseq @ 1 @ V_i )
& ( $lesseq @ V_i @ V_j )
& ( $lesseq @ V_j @ V_m )
& ( $lesseq @ ( $sum @ ( 'nth/2' @ $int @ ( $difference @ V_i @ 1 ) @ V_an ) @ ( 'nth/2' @ $int @ ( $difference @ V_j @ 1 ) @ V_an ) ) @ V_n ) )
=> ? [V_k: $int] :
( ( $lesseq @ 1 @ V_k )
& ( $lesseq @ V_k @ V_m )
& ( ( $sum @ ( 'nth/2' @ $int @ ( $difference @ V_i @ 1 ) @ V_an ) @ ( 'nth/2' @ $int @ ( $difference @ V_j @ 1 ) @ V_an ) )
= ( 'nth/2' @ $int @ ( $difference @ V_k @ 1 ) @ V_an ) ) ) ) )
=> ( $greatereq @ ( $quotient @ ( $to_rat @ ( 'int.sum/1' @ V_an ) ) @ ( $to_rat @ V_m ) ) @ ( $quotient @ ( $to_rat @ ( $sum @ V_n @ 1 ) ) @ ( $to_rat @ 2 ) ) ) ) ).
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