0.05/0.10 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.05/0.11 % Command : run_portfolio.sh /export/starexec/sandbox2/benchmark/theBenchmark.p /export/starexec/sandbox2/tmp/tmp.JLpNT9zcHo 0.10/0.31 % Computer : n009.cluster.edu 0.10/0.31 % Model : x86_64 x86_64 0.10/0.31 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.10/0.31 % Memory : 8042.1875MB 0.10/0.31 % OS : Linux 3.10.0-693.el7.x86_64 0.10/0.31 % CPULimit : 960 0.10/0.31 % DateTime : Thu Jul 2 08:08:51 EDT 2020 0.10/0.32 % CPUTime : 0.10/0.32 % Running portfolio for 120 s 0.10/0.32 % File : /export/starexec/sandbox2/benchmark/theBenchmark.p 0.10/0.32 % Number of cores: 8 0.10/0.32 % Python version: Python 3.6.8 0.10/0.32 % Running in FO mode 78.03/78.49 % Running /export/starexec/sandbox2/solver/bin/fo/fo7.sh for 25 78.03/78.49 % Running /export/starexec/sandbox2/solver/bin/fo/fo8.sh for 20 78.03/78.49 % Running /export/starexec/sandbox2/solver/bin/fo/fo5.sh for 20 78.03/78.49 % Running /export/starexec/sandbox2/solver/bin/fo/fo11.sh for 20 78.03/78.49 % Solved by: fo/fo11.sh 78.03/78.49 To remain in the chosen logic fragment, unification with booleans has been disabled. 78.03/78.49 % done 3527 iterations in 13.387s 78.03/78.49 % SZS status Theorem for '/export/starexec/sandbox2/benchmark/theBenchmark.p' 78.03/78.49 % SZS output start Refutation 78.03/78.49 tff(ax28, axiom, (![U]: (ssList(U) => (U = app(nil,U))))). 78.03/78.49 tff('0', plain, ![X57]: (X57 = app(nil, X57) | ~ ssList(X57)), 78.03/78.49 inference('cnf', [status(esa)], [ax28])). 78.03/78.49 tff(co1, conjecture, 78.03/78.49 (![U]: 78.03/78.49 (ssList(U) => 78.03/78.49 (![V]: 78.03/78.49 (ssList(V) => 78.03/78.49 (![W]: 78.03/78.49 (ssList(W) => 78.03/78.49 (![X]: 78.03/78.49 (ssList(X) => 78.03/78.49 ((X != V) | (W != U) | 78.03/78.49 ((![X3]: 78.03/78.49 (ssItem(X3) => 78.03/78.49 ((~memberP(X,X3)) | 78.03/78.49 (?[X4]: 78.03/78.49 (ssItem(X4) & leq(X3,X4) & memberP(X,X4) & 78.03/78.49 (X4 != X3))) | 78.03/78.49 (W != cons(X3,nil))))) & 78.03/78.49 ((nil != X) | (nil != W))) | 78.03/78.49 (?[Y]: 78.03/78.49 ((?[Z]: 78.03/78.49 (ssList(Z) & 78.03/78.49 (?[X1]: 78.03/78.49 (ssList(X1) & 78.03/78.49 (app(app(Z,cons(Y,nil)),X1) = U) & 78.03/78.49 (![X2]: 78.03/78.49 (ssItem(X2) => 78.03/78.49 ((~memberP(Z,X2)) | (~lt(Y,X2)) | 78.03/78.49 leq(Y,X2) | (~memberP(X1,X2))))))))) & 78.03/78.49 ssItem(Y))) | 78.03/78.49 (nil = U))))))))))). 78.03/78.49 tff(zf_stmt_0, negated_conjecture, 78.03/78.49 (~ 78.03/78.49 (![U]: 78.03/78.49 (ssList(U) => 78.03/78.49 (![V]: 78.03/78.49 (ssList(V) => 78.03/78.49 (![W]: 78.03/78.49 (ssList(W) => 78.03/78.49 (![X]: 78.03/78.49 (ssList(X) => 78.03/78.49 ((X != V) | (W != U) | 78.03/78.49 ((![X3]: 78.03/78.49 (ssItem(X3) => 78.03/78.49 ((~memberP(X,X3)) | 78.03/78.49 (?[X4]: 78.03/78.49 (ssItem(X4) & leq(X3,X4) & memberP(X,X4) & 78.03/78.49 (X4 != X3))) | 78.03/78.49 (W != cons(X3,nil))))) & 78.03/78.49 ((nil != X) | (nil != W))) | 78.03/78.49 (?[Y]: 78.03/78.49 ((?[Z]: 78.03/78.49 (ssList(Z) & 78.03/78.49 (?[X1]: 78.03/78.49 (ssList(X1) & 78.03/78.49 (app(app(Z,cons(Y,nil)),X1) = U) & 78.03/78.49 (![X2]: 78.03/78.49 (ssItem(X2) => 78.03/78.49 ((~memberP(Z,X2)) | (~lt(Y,X2)) | 78.03/78.49 leq(Y,X2) | (~memberP(X1,X2))))))))) & 78.03/78.49 ssItem(Y))) | 78.03/78.49 (nil = U)))))))))))). 78.03/78.49 tff('1', plain, (sk_W_12 = cons(sk_X3, nil) | nil = sk_W_12), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('2', plain, sk_W_12 = sk_U_1, 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('3', plain, sk_W_12 = sk_U_1, 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('4', plain, (sk_U_1 = cons(sk_X3, nil) | nil = sk_U_1), 78.03/78.49 inference('demod', [status(thm)], ['1', '2', '3'])). 78.03/78.49 tff('5', plain, nil != sk_U_1, inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('6', plain, sk_U_1 = cons(sk_X3, nil), 78.03/78.49 inference('simplify_reflect-', [status(thm)], ['4', '5'])). 78.03/78.49 tff('7', plain, sk_U_1 = cons(sk_X3, nil), 78.03/78.49 inference('simplify_reflect-', [status(thm)], ['4', '5'])). 78.03/78.49 tff(ax23, axiom, 78.03/78.49 (![U]: (ssList(U) => (![V]: (ssItem(V) => (hd(cons(V,U)) = V)))))). 78.03/78.49 tff('8', plain, 78.03/78.49 ![X120, X121]: 78.03/78.49 (~ ssItem(X120) | hd(cons(X120, X121)) = X120 | ~ ssList(X121)), 78.03/78.49 inference('cnf', [status(esa)], [ax23])). 78.03/78.49 tff('9', plain, (~ ssItem(sk_X3) | hd(sk_U_1) = sk_X3 | ~ ssList(nil)), 78.03/78.49 inference('s_sup+', [status(thm)], ['7', '8'])). 78.03/78.49 tff('10', plain, ( ssItem(sk_X3) | nil = sk_W_12), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('11', plain, sk_W_12 = sk_U_1, 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('12', plain, ( ssItem(sk_X3) | nil = sk_U_1), 78.03/78.49 inference('demod', [status(thm)], ['10', '11'])). 78.03/78.49 tff('13', plain, nil != sk_U_1, inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('14', plain, ssItem(sk_X3), 78.03/78.49 inference('simplify_reflect-', [status(thm)], ['12', '13'])). 78.03/78.49 tff(ax17, axiom, (ssList(nil))). 78.03/78.49 tff('15', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('16', plain, hd(sk_U_1) = sk_X3, 78.03/78.49 inference('demod', [status(thm)], ['9', '14', '15'])). 78.03/78.49 tff('17', plain, sk_U_1 = cons(hd(sk_U_1), nil), 78.03/78.49 inference('demod', [status(thm)], ['6', '16'])). 78.03/78.49 tff('18', plain, 78.03/78.49 ![X197, X198, X199]: 78.03/78.49 (~ ssList(X197) 78.03/78.49 | app(app(X198, cons(X199, nil)), X197) != sk_U_1 78.03/78.49 | ssItem(sk_X2(X197, X198, X199)) 78.03/78.49 | ~ ssList(X198) 78.03/78.49 | ~ ssItem(X199)), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('19', plain, 78.03/78.49 ![X197, X198, X199]: 78.03/78.49 (~ ssList(X197) 78.03/78.49 | app(app(X198, cons(X199, nil)), X197) != sk_U_1 78.03/78.49 | memberP(X197, sk_X2(X197, X198, X199)) 78.03/78.49 | ~ ssList(X198) 78.03/78.49 | ~ ssItem(X199)), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff(ax38, axiom, (![U]: (ssItem(U) => (~memberP(nil,U))))). 78.03/78.49 tff('20', plain, ![X183]: (~ memberP(nil, X183) | ~ ssItem(X183)), 78.03/78.49 inference('cnf', [status(esa)], [ax38])). 78.03/78.49 tff('21', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (~ ssItem(X0) 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | app(app(X1, cons(X0, nil)), nil) != sk_U_1 78.03/78.49 | ~ ssList(nil) 78.03/78.49 | ~ ssItem(sk_X2(nil, X1, X0))), 78.03/78.49 inference('s_sup-', [status(thm)], ['19', '20'])). 78.03/78.49 tff('22', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('23', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (~ ssItem(X0) 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | app(app(X1, cons(X0, nil)), nil) != sk_U_1 78.03/78.49 | ~ ssItem(sk_X2(nil, X1, X0))), 78.03/78.49 inference('demod', [status(thm)], ['21', '22'])). 78.03/78.49 tff('24', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (~ ssItem(X0) 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | app(app(X1, cons(X0, nil)), nil) != sk_U_1 78.03/78.49 | ~ ssList(nil) 78.03/78.49 | ~ ssItem(X0) 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | app(app(X1, cons(X0, nil)), nil) != sk_U_1), 78.03/78.49 inference('s_sup-', [status(thm)], ['18', '23'])). 78.03/78.49 tff('25', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('26', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (~ ssItem(X0) 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | app(app(X1, cons(X0, nil)), nil) != sk_U_1 78.03/78.49 | ~ ssItem(X0) 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | app(app(X1, cons(X0, nil)), nil) != sk_U_1), 78.03/78.49 inference('demod', [status(thm)], ['24', '25'])). 78.03/78.49 tff('27', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (app(app(X1, cons(X0, nil)), nil) != sk_U_1 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | ~ ssItem(X0)), 78.03/78.49 inference('simplify', [status(thm)], ['26'])). 78.03/78.49 tff('28', plain, 78.03/78.49 ![X0]: 78.03/78.49 (app(app(X0, sk_U_1), nil) != sk_U_1 78.03/78.49 | ~ ssList(X0) 78.03/78.49 | ~ ssItem(hd(sk_U_1))), 78.03/78.49 inference('s_sup-', [status(thm)], ['17', '27'])). 78.03/78.49 tff('29', plain, ssItem(sk_X3), 78.03/78.49 inference('simplify_reflect-', [status(thm)], ['12', '13'])). 78.03/78.49 tff('30', plain, hd(sk_U_1) = sk_X3, 78.03/78.49 inference('demod', [status(thm)], ['9', '14', '15'])). 78.03/78.49 tff('31', plain, ssItem(hd(sk_U_1)), 78.03/78.49 inference('demod', [status(thm)], ['29', '30'])). 78.03/78.49 tff('32', plain, ![X0]: (app(app(X0, sk_U_1), nil) != sk_U_1 | ~ ssList(X0)), 78.03/78.49 inference('demod', [status(thm)], ['28', '31'])). 78.03/78.49 tff('33', plain, 78.03/78.49 (~ ssList(sk_U_1) | app(sk_U_1, nil) != sk_U_1 | ~ ssList(nil)), 78.03/78.49 inference('s_sup-', [status(thm)], ['0', '32'])). 78.03/78.49 tff('34', plain, ssList(sk_U_1), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff(ax6, axiom, 78.03/78.49 (![U]: 78.03/78.49 (ssList(U) => 78.03/78.49 (![V]: 78.03/78.49 (ssList(V) => 78.03/78.49 ((?[W]: ((app(W,V) = U) & ssList(W))) <=> rearsegP(U,V))))))). 78.03/78.49 tff('35', plain, 78.03/78.49 ![X149, X150]: 78.03/78.49 (~ ssList(X149) 78.03/78.49 | ~ rearsegP(X150, X149) 78.03/78.49 | ssList(sk_W_9(X149, X150)) 78.03/78.49 | ~ ssList(X150)), 78.03/78.49 inference('cnf', [status(esa)], [ax6])). 78.03/78.49 tff('36', plain, 78.03/78.49 ![X149, X150]: 78.03/78.49 (~ ssList(X149) 78.03/78.49 | ~ rearsegP(X150, X149) 78.03/78.49 | app(sk_W_9(X149, X150), X149) = X150 78.03/78.49 | ~ ssList(X150)), 78.03/78.49 inference('cnf', [status(esa)], [ax6])). 78.03/78.49 tff('37', plain, sk_U_1 = cons(hd(sk_U_1), nil), 78.03/78.49 inference('demod', [status(thm)], ['6', '16'])). 78.03/78.49 tff('38', plain, sk_U_1 = cons(hd(sk_U_1), nil), 78.03/78.49 inference('demod', [status(thm)], ['6', '16'])). 78.03/78.49 tff(ax81, axiom, 78.03/78.49 (![U]: 78.03/78.49 (ssList(U) => (![V]: (ssItem(V) => (app(cons(V,nil),U) = cons(V,U))))))). 78.03/78.49 tff('39', plain, 78.03/78.49 ![X74, X75]: 78.03/78.49 (~ ssItem(X74) 78.03/78.49 | app(cons(X74, nil), X75) = cons(X74, X75) 78.03/78.49 | ~ ssList(X75)), 78.03/78.49 inference('cnf', [status(esa)], [ax81])). 78.03/78.49 tff('40', plain, 78.03/78.49 ![X0]: 78.03/78.49 (~ ssItem(hd(sk_U_1)) 78.03/78.49 | app(sk_U_1, X0) = cons(hd(sk_U_1), X0) 78.03/78.49 | ~ ssList(X0)), 78.03/78.49 inference('s_sup+', [status(thm)], ['38', '39'])). 78.03/78.49 tff('41', plain, ssItem(hd(sk_U_1)), 78.03/78.49 inference('demod', [status(thm)], ['29', '30'])). 78.03/78.49 tff('42', plain, 78.03/78.49 ![X0]: (app(sk_U_1, X0) = cons(hd(sk_U_1), X0) | ~ ssList(X0)), 78.03/78.49 inference('demod', [status(thm)], ['40', '41'])). 78.03/78.49 tff(ax79, axiom, 78.03/78.49 (![U]: 78.03/78.49 (ssList(U) => 78.03/78.49 (![V]: 78.03/78.49 (ssList(V) => 78.03/78.49 (![W]: (ssList(W) => ((app(W,V) = app(U,V)) => (W = U))))))))). 78.03/78.49 tff('43', plain, 78.03/78.49 ![X58, X59, X60]: 78.03/78.49 (~ ssList(X58) 78.03/78.49 | app(X60, X58) != app(X59, X58) 78.03/78.49 | X60 = X59 78.03/78.49 | ~ ssList(X60) 78.03/78.49 | ~ ssList(X59)), 78.03/78.49 inference('cnf', [status(esa)], [ax79])). 78.03/78.49 tff('44', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (~ ssList(X0) 78.03/78.49 | ~ ssList(X0) 78.03/78.49 | app(X1, X0) != cons(hd(sk_U_1), X0) 78.03/78.49 | X1 = sk_U_1 78.03/78.49 | ~ ssList(X1) 78.03/78.49 | ~ ssList(sk_U_1)), 78.03/78.49 inference('s_sup-', [status(thm)], ['42', '43'])). 78.03/78.49 tff('45', plain, ssList(sk_U_1), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('46', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (~ ssList(X0) 78.03/78.49 | ~ ssList(X0) 78.03/78.49 | app(X1, X0) != cons(hd(sk_U_1), X0) 78.03/78.49 | X1 = sk_U_1 78.03/78.49 | ~ ssList(X1)), 78.03/78.49 inference('demod', [status(thm)], ['44', '45'])). 78.03/78.49 tff('47', plain, 78.03/78.49 ![X0, X1]: 78.03/78.49 (~ ssList(X1) 78.03/78.49 | X1 = sk_U_1 78.03/78.49 | app(X1, X0) != cons(hd(sk_U_1), X0) 78.03/78.49 | ~ ssList(X0)), 78.03/78.49 inference('simplify', [status(thm)], ['46'])). 78.03/78.49 tff('48', plain, 78.03/78.49 ![X0]: 78.03/78.49 (~ ssList(X0) | X0 = sk_U_1 | app(X0, nil) != sk_U_1 | ~ ssList(nil)), 78.03/78.49 inference('s_sup-', [status(thm)], ['37', '47'])). 78.03/78.49 tff('49', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('50', plain, 78.03/78.49 ![X0]: (~ ssList(X0) | X0 = sk_U_1 | app(X0, nil) != sk_U_1), 78.03/78.49 inference('demod', [status(thm)], ['48', '49'])). 78.03/78.49 tff('51', plain, 78.03/78.49 ![X0]: 78.03/78.49 (~ ssList(X0) 78.03/78.49 | ~ rearsegP(X0, nil) 78.03/78.49 | ~ ssList(nil) 78.03/78.49 | ~ ssList(sk_W_9(nil, X0)) 78.03/78.49 | sk_W_9(nil, X0) = sk_U_1 78.03/78.49 | X0 != sk_U_1), 78.03/78.49 inference('s_sup-', [status(thm)], ['36', '50'])). 78.03/78.49 tff('52', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('53', plain, 78.03/78.49 ![X0]: 78.03/78.49 (~ ssList(X0) 78.03/78.49 | ~ rearsegP(X0, nil) 78.03/78.49 | ~ ssList(sk_W_9(nil, X0)) 78.03/78.49 | sk_W_9(nil, X0) = sk_U_1 78.03/78.49 | X0 != sk_U_1), 78.03/78.49 inference('demod', [status(thm)], ['51', '52'])). 78.03/78.49 tff('54', plain, 78.03/78.49 (sk_W_9(nil, sk_U_1) = sk_U_1 78.03/78.49 | ~ ssList(sk_W_9(nil, sk_U_1)) 78.03/78.49 | ~ rearsegP(sk_U_1, nil) 78.03/78.49 | ~ ssList(sk_U_1)), 78.03/78.49 inference('simplify', [status(thm)], ['53'])). 78.03/78.49 tff('55', plain, ssList(sk_U_1), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('56', plain, ssList(sk_U_1), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff(ax51, axiom, (![U]: (ssList(U) => rearsegP(U,nil)))). 78.03/78.49 tff('57', plain, ![X169]: ( rearsegP(X169, nil) | ~ ssList(X169)), 78.03/78.49 inference('cnf', [status(esa)], [ax51])). 78.03/78.49 tff('58', plain, rearsegP(sk_U_1, nil), 78.03/78.49 inference('s_sup-', [status(thm)], ['56', '57'])). 78.03/78.49 tff('59', plain, 78.03/78.49 (sk_W_9(nil, sk_U_1) = sk_U_1 | ~ ssList(sk_W_9(nil, sk_U_1))), 78.03/78.49 inference('simplify_reflect+', [status(thm)], ['54', '55', '58'])). 78.03/78.49 tff('60', plain, 78.03/78.49 (~ ssList(sk_U_1) 78.03/78.49 | ~ rearsegP(sk_U_1, nil) 78.03/78.49 | ~ ssList(nil) 78.03/78.49 | sk_W_9(nil, sk_U_1) = sk_U_1), 78.03/78.49 inference('s_sup-', [status(thm)], ['35', '59'])). 78.03/78.49 tff('61', plain, ssList(sk_U_1), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('62', plain, rearsegP(sk_U_1, nil), 78.03/78.49 inference('s_sup-', [status(thm)], ['56', '57'])). 78.03/78.49 tff('63', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('64', plain, sk_W_9(nil, sk_U_1) = sk_U_1, 78.03/78.49 inference('demod', [status(thm)], ['60', '61', '62', '63'])). 78.03/78.49 tff('65', plain, 78.03/78.49 ![X149, X150]: 78.03/78.49 (~ ssList(X149) 78.03/78.49 | ~ rearsegP(X150, X149) 78.03/78.49 | app(sk_W_9(X149, X150), X149) = X150 78.03/78.49 | ~ ssList(X150)), 78.03/78.49 inference('cnf', [status(esa)], [ax6])). 78.03/78.49 tff('66', plain, 78.03/78.49 (~ ssList(nil) 78.03/78.49 | ~ rearsegP(sk_U_1, nil) 78.03/78.49 | app(sk_U_1, nil) = sk_U_1 78.03/78.49 | ~ ssList(sk_U_1)), 78.03/78.49 inference('s_sup+', [status(thm)], ['64', '65'])). 78.03/78.49 tff('67', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('68', plain, rearsegP(sk_U_1, nil), 78.03/78.49 inference('s_sup-', [status(thm)], ['56', '57'])). 78.03/78.49 tff('69', plain, ssList(sk_U_1), 78.03/78.49 inference('cnf', [status(esa)], [zf_stmt_0])). 78.03/78.49 tff('70', plain, app(sk_U_1, nil) = sk_U_1, 78.03/78.49 inference('demod', [status(thm)], ['66', '67', '68', '69'])). 78.03/78.49 tff('71', plain, ssList(nil), inference('cnf', [status(esa)], [ax17])). 78.03/78.49 tff('72', plain, sk_U_1 != sk_U_1, 78.03/78.49 inference('demod', [status(thm)], ['33', '34', '70', '71'])). 78.03/78.49 tff('73', plain, $false, inference('simplify', [status(thm)], ['72'])). 78.03/78.49 78.03/78.49 % SZS output end Refutation 78.03/78.49 78.03/78.50 % Zipperpin 1.5 exiting 78.03/78.50 EOF