Quantified constraints over the reals appear in numerous contexts. Usually existential quantification occurs when some parameter can be chosen by the user of a system, and univeral quantification when the exact value of a parameter is either unknown, or when it occurs in infinitely many, similar versions.
The following is a list of application areas and publications that contain applications for solving quantified constraints over the reals. The list is certainly not complete, but grows as the author encounters new items. Contributions are very welcome!
Thanks to Hirokazu Anai for contributing references.
A collection of examples from the above papers. I am thankful for any contribution!
FORALL([p], [[0, 1]], 9 + 48 p + 48 q + 32 p q > 0 /\ 1 + p + q > 0 /\ -16 p - 16 q + 16 p^2 + 16 q^2 + 7 > 0 ); [q]; [[-2, 2]];Solution: [35]: 4q-1<0 /\16q+3>0 /\4q-3>0, that is (-0.1875, 0.25) union (0.75, infty).
FORALL([q1, q2, ww], [[0.8, 1.25], [0.8, 1.25], [0.0, infty]], -k2 - k1 q1 > 0 /\ - q1 k1 - 50 > 0 /\ 2 k2^2 ww^2 + 4 k2^2 ww k1 q1 q2 + k2^2 k1^2 q1^2 q2^2 + 2 k2^2 ww q2^2 + 4 k2 ww k1 q1 q2^2 + ww k1^2 q1^2 q2^2 > 0 /\ 400 k2^2 ww^2 + 800 k2^2 ww k1 q1 q2 + 400 k2^2 k1^2 q1^2 q2^2 + 400 k2^2 ww q2^2 + 800 k2 ww k1 q1 q2^2 + 400 ww k1^2 q1^2 q2^2 - k2^2 k1^2 q2^2 - ww^2 k1^2 - k2^2 ww k1^2 - ww k1^2 q2^2 > 0 ); [k1, k2]; [[-200, 0], [0, 10]];
FORALL([ p1, p2 ], [ [0.8, 1.25], [0.8, 1.25]], p2*(1+p1*q1) < 0 /\ FORALL([w1], [[0,10]], 99*w1^2 + p2^2 * (100*(1+p1*q1)^2 - 1) > 0) /\ FORALL([w2], [[-infty,infty]], (400-q1^2)*w2^2 + p2^2*(400*(1+p1*q1)^2-q1^2) > 0) ); [q1]; [ [-50, 10] ];Solution [38]: -20 <= q1 < -1.375
FORALL([p1, p2, p3, p4], [[2.5, 3.5], [1.5, 2.5], [2.5, 3.5], [9.5, 10.5]], p2 q2 + p4 q4 > 0 /\ p4 + q4 + p1 q1 - p3 q3 > 0 /\ p1 p3 q2 q4 - p1 p3 q2 p4 - p2 q1 p3 p4 - 2 p1 p2 q1 q2 - p1 q2 p4 q3 + p2 q1 p3 q4 - p2 q1 p4 q3 + 2 p2 p3 q2 q3 + p1 q2 q3 q4 + p2 q1 q3 q4 + 2 p3 p4 q3 q4 - p1 q1 p3 p4 q3 - p1 q1 p3 q3 q4 - p2 p3^2 q2 - p2 q2 q3^2 - p3 p4^2 q3 - p3 p4 q3^3 - p3 q3 q4^2 - p3^3 q3 q4 - p1 p2 q1^2 p3 + p1 p2 q1^2 q3 - p1^2 q1 p3 q2 + p1^2 q1 q2 q3 + p1 q1 p4 q3^2 + p1 q1 p3^2 q4 - p1 p3 q2 q3^2 + p1 p3^2 q2 q3 - p2 q1 p3 q3^2 + p2 q1 p3^2 q3 - p1^2 q2^2 - p2^2 q1^2 + p3^2 p4 q3^2 + p3^2 q3^2 q4 > 0 /\ q3 - p3 > 0 ); [q1, q2, q3, q4]; [[19, 21], [22, 24], [9, 11], [4, 5]];
FORALL([z, T, w0, K], [[0.95, 1.05], [-1.05, -0.95], [0.95, 1.05], [0.95, 1.05]], K c1 w0^2 < 0 /\ 2 z T w0 + 1 < 0 /\ (2 z w0 + w0^2 T + w0^2 T c3)*(2 z T w0 + 1) - w0^2 (K*c2+1) < 0 /\ w0^2*(K*c2 + 1)*(2*T*z*w0 + 1)*(2*z*w0 + w0^2*(T + K*c3)) - K*c1*w0^2*(2*T*z*w0 + 1)^2 - w0^4*(K*c2 + 1)^2 < 0 ); [ c1, c2, c3 ]; [[ -10, 10], [-10, 10], [-10, 10]];
FORALL([p1, p2, p3], [[0.9, 1.1], [0.9, 1.1], [0.9, 1.1]], (1 + c2*p1 )*( (p2*p3^2 +p3)*(p2*p3 +1) - p2*(p3^2 +c2*p1*p3^2)) - (p2*p3 + 1)^2*(c1*p1) > 0 /\ (p2*p3 + 1)*(p2*p3 + 1) - p2*( p3 + c2*p1*p3) > 0 /\ c1*p1*p3^2 > 0 ); [c1, c2]; [[0, 1], [0, 1]];
EXISTS([A, B, D, P1, P2, P3, P4, P5, P6, P7, P8, P9], P1 > 0 /\ P2 > 0 /\ P3 > 0 /\ P4 P5 > 0 /\ A > 0 /\ B P6 P7 > 0 /\ P8 P9 > 0 /\ P1 = A B^2 - D^2 /\ P2 = - A B + A + D^2 - D - 1 /\ P3 = A B - A D - 2 A + D^3 + 4 D^2 + 4 D /\ P4 = A B - 2 A - B D^2 - 4 B D - 4 B + 2 D^2 + 5 D + 2 /\ P5 = A B^3 - A B^2 D - 4 A B^2 + 2 A B D + 4 A B + 2 B D^3 + 5 B D^2 + 2 B D - D^3 - 4 D^2 - 4 D /\ P6 = A B - 2 A - B D^2 - 4 B D - 4 B + 2 D^2 + 4 D /\ P7 = A B^2 - A B D - 4 A B + 2 A D + 4 A + 2 D^3 + 4 D^2 /\ P8 = A B - 2 A - B D^2 - 4 B D - 4 B + 2 D^2 + 3 D - 2 /\ P9 = A B^3 - A B^2 D - 4 A B^2 + 2 A B D + 4 A B + 2 B D^3 + 3 B D^2 - 2 B D + D^3 + 4 D^2 + 4 D );Solution: True, witness: A=110, B=3/2, D=15
FORALL([c, t, r, h, d, v],
(r>0 /\ t>0 /\ c<1 /\ d>0 /\ v>0) ==>
((d+1)(v+t+1) = r h (c t + d + 1) ==> -(d+1)(v d + v + t d + t + d + 1 - h r c t - h r d - h r)=0))
Solution [27]: True
FORALL([r2, p1],
(r2>1/2 ==>
(4 (180 + 180 r2^2) = 75 (12+6 r2) /\
(8 + 24 p1 + 20 r2 - 16 r2^2 p1 + 198 r2^2 p1^2 + 95 p1 r2 + 185 r2 p1^2 - 32 r2^2 - 32 p1^2) p1 = 0) ==> p1 <= 0 ))
Solution [27]: True
FORALL([r1, r2, p1],
(r2>0 /\ r1>0 /\ r2>r1) ==>
(( 4 (720 r1^2 + 180 r2^2)= 75 (24 r1 + 6 r2) /\
(-88 r1 r2^2 p1^2 + 56 r1 r2^2 p1 - 480 r1^2 p1^2 r2 - 335 r1 p1 r2 + 55 r2 r1
p1^2 + 480 r1^2 p1 r2 - 80 r1^2 + 128 r1^3 + 80 r1^2 p1 - 20 r2^2 p1 - 20 r2 p1 - 55
r2^2 p1^2 - 256 r1^3 p1 + 128 r1^3 p1^2 + 32 r1 r2^2) p1 = 0) ==> p1 <= 0)
Solution [27]: True
FORALL([g2, p1],
(r2>0 /\ r1>0 /\ r2>r1 /\ 0<g2 /\ g2 < 1/2) ==>
(( 4 (900 r1^2 (1-g2) + 900 r2^2 g2 ) = 75 (30 r1 (1-g2) + 30 r2 g2) /\
(55 r2^2 g2 p1^2 + 20 r2^2 g2 p1 + 20 r2 g2 r1 - 40 r2 g2 r1 p1 + 20 r1^2 - 20
r1^2 g2 - 32 r1^3 + 32 r1^3 g2 + 75 r1 p1 r2 - 55 r2 g2 r1 p1^2 - 120 r1^2 p1 r2 + 120
r1^2 p1 r2 g2 + 120 r1^2 p1^2 r2 - 120 r1^2 p1^2 r2 g2 - 56 r1 r2^2 g2 p1 + 88 r1 r2^2
g2 p1^2 - 32 r1^3 p1^2 + 32 r1^3 p1^2 g2 - 20 r1^2 p1 + 20 r1^2 p1 g2 + 64 r1^3 p1 -
64 r1^3 p1 g2 - 32 r1 r2^2 g2) p1 = 0 ) ==> p1 <= 0))
Solution [27]: True
FORALL([p1], (t > 0) ==> (( 2 (48 t + 7) = 7 (1 + 8 t) /\ -3472875 p1 - 26162325 p1^2 + 10584000 t - 69325200 t p1 - 327499200 t^2 p1 - 578283300 t p1^2 - 4222108800 t^2 p1^2 - 10163232000 t^3 p1^2 + 1852200 = 0) ==> (p1 <= 0)))Solution [27]: True
FORALL([p1], (t > 0 /\ 0 < c /\ c < 1) ==> (( 2 (60 c t + 7) = 7 (1 + 8 t) /\ 139179600 t p1 - 87318000 c t p1 - 662256000 c t^2 p1 + 357210000 t p1^2 c + 5765256000 t^2 p1^2 c + 3472875 p1 + 14817600 t + 26162325 p1^2 + 23250240000 c t^3 p1^2 + 292515300 t p1^2 + 857304000 t^2 p1 - 390096000 t^2 p1^2 - 31752000 c t - 8436960000 t^3 p1^2 - 1852200 = 0) ==> (p1 <= 0))Solution [27]: True
FORALL([p1], (t > 0 /\ 2 r2 > 1) ==> (( 8 (1+r2^2) (1+ 6 t) = (2 + r2) 5 (1 + 8 t) /\ -370440 - 1111320 p1 + 8678880 r2^2 t p1 - 926100 r2 + 25401600 r2^2 t^2 p1 - 3538080000 r2^2 t^3 p1^2 + 1481760 p1^2 + 29529360 t p1^2 - 91551600 t p1 r2 - 153071100 t p1^2 r2 - 791985600 t^2 p1^2 r2 - 202127940 r2^2 t p1^2 - 1472385600 r2^2 t^2 p1^2 - 5927040 t + 740880 r2^2 p1 - 4398975 p1 r2 - 7726320 t p1 + 182347200 t^2 p1^2 - 9168390 r2^2 p1^2 - 8566425 r2 p1^2 + 8890560 r2^2 t + 1481760 r2^2 - 450878400 t^2 p1 r2 - 925344000 t^3 p1^2 r2 - 7408800 t r2 + 12700800 t^2 p1 + 326592000 t^3 p1^2 = 0) ==> (p1 <= 0)))Solution [27]: True
EXISTS([u], [[-0.5, 0.5]], -x1 + x2 u = 0 /\ -x2 + (1+x1^2) u + u^3 = 0 )Solution [63]:
x2^4 - x1^3 x2^2 - x1 x2^2 - x1^3 = 0 /\ (x2 + 2 x1 <= 0 \/ x2 - 2 x1 >= 0)
FORALL([t], [[0, 1]]
EXISTS([u, l], [[-1,1], (0, \infty]],
-t + 2 = l /\ -(3 t^2 - 2 t^3) - t^2 + 4 u = l ( 6 t - 6 t^2 ) ))
EXISTS([z], [[ 1, \infty ]], x2 >= 3 /\ x1 z^2 = 4 /\ (2 x2 - 1) + z^2 = 6 z )Solution: x2 >= 3 /\4 x12 x22 - 4 x12 x2 + 16 x1 x2 + x12 - 152 x1 + 16 = 0
EXISTS([a, z], [[ 0, 1 ], [ 1, \infty ]], y1 = 2/3 a (-z^4 + z) /\ y2 z^2 = 1/2 a (z^4 - 1) )
EXISTS([z], [[ 1, \infty ]], 3 y1 (z^3 + z^2 + z + 1) + 4 y2 (z^5 + z^4 + z^3) = 0 )Solution: (y2>0 /\y1+y2 <= 0) \/(y2<0/\y1+y2 >= 0) \/4 y2 + 3 y1 = 0
EXISTS([w, z], [[-2,2], [-2,2]], w^2+z^2 = 1 /\ 0 = (z^2-w^2)-2/3 w /\ y2 = - 4 z w - 5/3 z ); [y2]; [[0, 4]];Solution: y2=(sqrt(-181sqrt(19)+908))/(9sqrt(2)) \/y2=(sqrt(181sqrt(19)+908))/(9sqrt(2))
EXISTS([w, z, a], [[-2,2], [-2,2], [0, \infty]], a>0 /\ w^2+z^2 = 1 /\ -3a = w ((4 a^2 - 2) z + 2 - a^2) /\ 3a = (a^2-2)(w^2-z^2+z) ); []; [];