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Statement List for Metamath Proof Explorer - 1101-1200 - Page 12 of 123
TypeLabelDescription
Statement
 
Theorem19.23bi 1101 Inference from Theorem 19.23 of [Margaris] p. 90.
|- (E.xph -> ps)   =>   |- (ph -> ps)
 
Theorem19.23ad 1102 Deduction from Theorem 19.23 of [Margaris] p. 90.
|- (ph -> A.xph)   &   |- (ch -> A.xch)   &   |- (ph -> (ps -> ch))   =>   |- (ph -> (E.xps -> ch))
 
Theorem19.26 1103 Theorem 19.26 of [Margaris] p. 90. Also Theorem *10.22 of [WhiteheadRussell] p. 119.
|- (A.x(ph /\ ps) <-> (A.xph /\ A.xps))
 
Theorem19.26-2 1104 Theorem 19.26 of [Margaris] p. 90 with two quantifiers.
|- (A.xA.y(ph /\ ps) <-> (A.xA.yph /\ A.xA.yps))
 
Theorem19.27 1105 Theorem 19.27 of [Margaris] p. 90.
|- (ps -> A.xps)   =>   |- (A.x(ph /\ ps) <-> (A.xph /\ ps))
 
Theorem19.28 1106 Theorem 19.28 of [Margaris] p. 90.
|- (ph -> A.xph)   =>   |- (A.x(ph /\ ps) <-> (ph /\ A.xps))
 
Theorem19.29 1107 Theorem 19.29 of [Margaris] p. 90.
|- ((A.xph /\ E.xps) -> E.x(ph /\ ps))
 
Theorem19.29r 1108 Variation of Theorem 19.29 of [Margaris] p. 90.
|- ((E.xph /\ A.xps) -> E.x(ph /\ ps))
 
Theorem19.29r2 1109 Variation of Theorem 19.29 of [Margaris] p. 90 with double quantification.
|- ((E.xE.yph /\ A.xA.yps) -> E.xE.y(ph /\ ps))
 
Theorem19.29x 1110 Variation of Theorem 19.29 of [Margaris] p. 90 with mixed quantification.
|- ((E.xA.yph /\ A.xE.yps) -> E.xE.y(ph /\ ps))
 
Theorem19.35 1111 Theorem 19.35 of [Margaris] p. 90. This theorem is useful for moving an implication (in the form of the right-hand side) into the scope of a single existential quantifier.
|- (E.x(ph -> ps) <-> (A.xph -> E.xps))
 
Theorem19.35i 1112 Inference from Theorem 19.35 of [Margaris] p. 90.
|- E.x(ph -> ps)   =>   |- (A.xph -> E.xps)
 
Theorem19.35ri 1113 Inference from Theorem 19.35 of [Margaris] p. 90.
|- (A.xph -> E.xps)   =>   |- E.x(ph -> ps)
 
Theorem19.36 1114 Theorem 19.36 of [Margaris] p. 90.
|- (ps -> A.xps)   =>   |- (E.x(ph -> ps) <-> (A.xph -> ps))
 
Theorem19.36i 1115 Inference from Theorem 19.36 of [Margaris] p. 90.
|- (ps -> A.xps)   &   |- E.x(ph -> ps)   =>   |- (A.xph -> ps)
 
Theorem19.37 1116 Theorem 19.37 of [Margaris] p. 90.
|- (ph -> A.xph)   =>   |- (E.x(ph -> ps) <-> (ph -> E.xps))
 
Theorem19.38 1117 Theorem 19.38 of [Margaris] p. 90.
|- ((E.xph -> A.xps) -> A.x(ph -> ps))
 
Theorem19.39 1118 Theorem 19.39 of [Margaris] p. 90.
|- ((E.xph -> E.xps) -> E.x(ph -> ps))
 
Theorem19.24 1119 Theorem 19.24 of [Margaris] p. 90.
|- ((A.xph -> A.xps) -> E.x(ph -> ps))
 
Theorem19.25 1120 Theorem 19.25 of [Margaris] p. 90.
|- (A.yE.x(ph -> ps) -> (E.yA.xph -> E.yE.xps))
 
Theorem19.30 1121 Theorem 19.30 of [Margaris] p. 90.
|- (A.x(ph \/ ps) -> (A.xph \/ E.xps))
 
Theorem19.32 1122 Theorem 19.32 of [Margaris] p. 90.
|- (ph -> A.xph)   =>   |- (A.x(ph \/ ps) <-> (ph \/ A.xps))
 
Theorem19.31 1123 Theorem 19.31 of [Margaris] p. 90.
|- (ps -> A.xps)   =>   |- (A.x(ph \/ ps) <-> (A.xph \/ ps))
 
Theorem19.43 1124 Theorem 19.43 of [Margaris] p. 90.
|- (E.x(ph \/ ps) <-> (E.xph \/ E.xps))
 
Theorem19.44 1125 Theorem 19.44 of [Margaris] p. 90.
|- (ps -> A.xps)   =>   |- (E.x(ph \/ ps) <-> (E.xph \/ ps))
 
Theorem19.45 1126 Theorem 19.45 of [Margaris] p. 90.
|- (ph -> A.xph)   =>   |- (E.x(ph \/ ps) <-> (ph \/ E.xps))
 
Theorem19.33 1127 Theorem 19.33 of [Margaris] p. 90.
|- ((A.xph \/ A.xps) -> A.x(ph \/ ps))
 
Theorem19.33b 1128 The antecedent provides a condition implying the converse of 19.33 1127. Compare Theorem 19.33 of [Margaris] p. 90.
|- (-. (E.xph /\ E.xps) -> (A.x(ph \/ ps) <-> (A.xph \/ A.xps)))
 
Theorem19.34 1129 Theorem 19.34 of [Margaris] p. 90.
|- ((A.xph \/ E.xps) -> E.x(ph \/ ps))
 
Theorem19.40 1130 Theorem 19.40 of [Margaris] p. 90.
|- (E.x(ph /\ ps) -> (E.xph /\ E.xps))
 
Theorem19.41 1131 Theorem 19.41 of [Margaris] p. 90.
|- (ps -> A.xps)   =>   |- (E.x(ph /\ ps) <-> (E.xph /\ ps))
 
Theorem19.42 1132 Theorem 19.42 of [Margaris] p. 90.
|- (ph -> A.xph)   =>   |- (E.x(ph /\ ps) <-> (ph /\ E.xps))
 
Theoremalrot4 1133 Rotate 4 universal quantifiers twice.
|- (A.xA.yA.zA.wph <-> A.zA.wA.xA.yph)
 
Theoremexcom13 1134 Swap 1st and 3rd existential quantifiers.
|- (E.xE.yE.zph <-> E.zE.yE.xph)
 
Theoremexrot3 1135 Rotate existential quantifiers.
|- (E.xE.yE.zph <-> E.yE.zE.xph)
 
Theoremexrot4 1136 Rotate existential quantifiers twice.
|- (E.xE.yE.zE.wph <-> E.zE.wE.xE.yph)
 
Theoremnex 1137 Generalization rule for negated wff.
|- -. ph   =>   |- -. E.xph
 
Theoremnexd 1138 Deduction for generalization rule for negated wff.
|- (ph -> A.xph)   &   |- (ph -> -. ps)   =>   |- (ph -> -. E.xps)
 
Theoremhbim1 1139 A closed form of hbim 1043.
|- (ph -> A.xph)   &   |- (ph -> (ps -> A.xps))   =>   |- ((ph -> ps) -> A.x(ph -> ps))
 
Theoremalbid 1140 Formula-building rule for universal quantifier (deduction rule).
|- (ph -> A.xph)   &   |- (ph -> (ps <-> ch))   =>   |- (ph -> (A.xps <-> A.xch))
 
Theoremexbid 1141 Formula-building rule for existential quantifier (deduction rule).
|- (ph -> A.xph)   &   |- (ph -> (ps <-> ch))   =>   |- (ph -> (E.xps <-> E.xch))
 
Theoremexan 1142 Place a conjunct in the scope of an existential quantifier.
|- (E.xph /\ ps)   =>   |- E.x(ph /\ ps)
 
Theoremalbi 1143 Split a biconditional and distribute quantifier.
|- (A.x(ph <-> ps) <-> (A.x(ph -> ps) /\ A.x(ps -> ph)))
 
Theorem2albi 1144 Split a biconditional and distribute 2 quantifiers.
|- (A.xA.y(ph <-> ps) <-> (A.xA.y(ph -> ps) /\ A.xA.y(ps -> ph)))
 
Theoremhbnd 1145 Deduction form of bound-variable hypothesis builder hbn 1040.
|- (ph -> A.xph)   &   |- (ph -> (ps -> A.xps))   =>   |- (ph -> (-. ps -> A.x -. ps))
 
Theoremhbimd 1146 Deduction form of bound-variable hypothesis builder hbim 1043.
|- (ph -> A.xph)   &   |- (ph -> (ps -> A.xps))   &   |- (ph -> (ch -> A.xch))   =>   |- (ph -> ((ps -> ch) -> A.x(ps -> ch)))
 
Theoremhband 1147 Deduction form of bound-variable hypothesis builder hban 1045.
|- (ph -> (ps -> A.xps))   &   |- (ph -> (ch -> A.xch))   =>   |- (ph -> ((ps /\ ch) -> A.x(ps /\ ch)))
 
Theoremhbbid 1148 Deduction form of bound-variable hypothesis builder hbbi 1046.
|- (ph -> A.xph)   &   |- (ph -> (ps -> A.xps))   &   |- (ph -> (ch -> A.xch))   =>   |- (ph -> ((ps <-> ch) -> A.x(ps <-> ch)))
 
Theoremhbald 1149 Deduction form of bound-variable hypothesis builder hbal 1041.
|- (ph -> A.yph)   &   |- (ph -> (ps -> A.xps))   =>   |- (ph -> (A.yps -> A.xA.yps))
 
Theoremhbexd 1150 Deduction form of bound-variable hypothesis builder hbex 1042.
|- (ph -> A.yph)   &   |- (ph -> (ps -> A.xps))   =>   |- (ph -> (E.yps -> A.xE.yps))
 
Theorem19.21t 1151 Closed form of Theorem 19.21 of [Margaris] p. 90.
|- (A.x(ph -> A.xph) -> (A.x(ph -> ps) <-> (ph -> A.xps)))
 
Theorem19.23t 1152 Closed form of Theorem 19.23 of [Margaris] p. 90.
|- (A.x(ps -> A.xps) -> (A.x(ph -> ps) <-> (E.xph -> ps)))
 
Theoremexintr 1153 Introduce a conjunct in the scope of an existential quantifier.
|- (A.x(ph -> ps) -> (E.xph -> E.x(ph /\ ps)))
 
Theoremexintrbi 1154 Add/remove a conjunct in the scope of an existential quantifier. (Contributed by Raph Levien, 3-Jul-2006.)
|- (A.x(ph -> ps) -> (E.xph <-> E.x(ph /\ ps)))
 
Theoremaaan 1155 Rearrange universal quantifiers.
|- (ph -> A.yph)   &   |- (ps -> A.xps)   =>   |- (A.xA.y(ph /\ ps) <-> (A.xph /\ A.yps))
 
Theoremeeor 1156 Rearrange existential quantifiers.
|- (ph -> A.yph)   &   |- (ps -> A.xps)   =>   |- (E.xE.y(ph \/ ps) <-> (E.xph \/ E.yps))
 
Theoremqexmid 1157 Quantified "excluded middle." Exercise 9.2a of Boolos, p. 111, Computability and Logic.
|- E.x(ph -> A.xph)
 
Equality
 
Theoremax9o 1158 Show that the original axiom ax-9o 1159 can be derived from ax-9 1001 and others. See ax9 1160 for the rederivation of ax-9 1001 from ax-9o 1159.

This theorem should not be referenced in any proof. Instead, use ax-9o 1159 below so that uses of ax-9o 1159 can be more easily identified.

|- (A.x(x = y -> A.xph) -> ph)
 
Axiomax-9o 1159 A variant of ax-9 1001. Axiom scheme C10' in [Megill] p. 448 (p. 16 of the preprint).

This axiom is redundant, as shown by theorem ax9o 1158.

|- (A.x(x = y -> A.xph) -> ph)
 
Theoremax9 1160 Rederivation of axiom ax-9 1001 from the orginal version, ax-9o 1159. See ax9o 1158 for the derivation of ax-9o 1159 from ax-9 1001. Lemma L18 in [Megill] p. 446 (p. 14 of the preprint).

This theorem should not be referenced in any proof. Instead, use ax-9 1001 above so that uses of ax-9 1001 can be more easily identified.

|- -. A.x -. x = y
 
Theorema9e 1161 At least one individual exists. This is not a theorem of free logic, which is sound in empty domains. For such a logic, we would add this theorem as an axiom of set theory (Axiom 0 of [Kunen] p. 10). In the system consisting of ax-5 996 through ax-14 1006 and ax-17 1007, all axioms other than ax-9 1001 are believed to be theorems of free logic, although the system without ax-9 1001 is probably not complete in free logic.
|- E.x x = y
 
Theoremequid 1162 Identity law for equality (reflexivity). Lemma 6 of [Tarski] p. 68. This is often an axiom of equality in textbook systems, but we don't need it as an axiom since it can be proved from our other axioms (although the proof, as you can see below, is not as obvious as you might think). This proof uses only axioms without distinct variable conditions and thus requires no dummy variables. A simpler proof, similar to Tarki's, is possible if we make use of ax-17 1007; see the proof of equid1 1307. See equidALT 1163 for an alternate proof.
|- x = x
 
TheoremequidALT 1163 Identity law for equality (reflexivity). Lemma 6 of [Tarski] p. 68. Alternate proof of equid 1162 directly from equality axioms ax-9 1001 and ax-12 1004.
|- x = x
 
Theoremstdpc6 1164 One of the two equality axioms of standard predicate calculus, called reflexivity of equality. (The other one is stdpc7 1217.) Axiom 6 of [Mendelson] p. 95. Mendelson doesn't say why he prepended the redundant quantifier, but it was probably to be compatible with free logic (which is valid in the empty domain).
|- A.x x = x
 
Theoremequcomi 1165 Commutative law for equality. Lemma 7 of [Tarski] p. 69.
|- (x = y -> y = x)
 
Theoremequcom 1166 Commutative law for equality.
|- (x = y <-> y = x)
 
Theoremequcoms 1167 An inference commuting equality in antecedent. Used to eliminate the need for a syllogism.
|- (x = y -> ph)   =>   |- (y = x -> ph)
 
Theoremequtr 1168 A transitive law for equality.
|- (x = y -> (y = z -> x = z))
 
Theoremequtrr 1169 A transitive law for equality. Lemma L17 in [Megill] p. 446 (p. 14 of the preprint).
|- (x = y -> (z = x -> z = y))
 
Theoremequtr2 1170 A transitive law for equality.
|- ((x = z /\ y = z) -> x = y)
 
Theoremequequ1 1171 An equivalence law for equality.
|- (x = y -> (x = z <-> y = z))
 
Theoremequequ2 1172 An equivalence law for equality.
|- (x = y -> (z = x <-> z = y))
 
Theoremelequ1 1173 An identity law for the non-logical predicate.
|- (x = y -> (x e. z <-> y e. z))
 
Theoremelequ2 1174 An identity law for the non-logical predicate.
|- (x = y -> (z e. x <-> z e. y))
 
Theoremax11i 1175 Inference that has ax-11 1003 (without A.y) as its conclusion and doesn't require ax-10 1002, ax-11 1003, or ax-12 1004 for its proof. The hypotheses may be eliminable without one or more of these axioms in special cases. Proof similar to Lemma 16 of [Tarski] p. 70.
|- (x = y -> (ph <-> ps))   &   |- (ps -> A.xps)   =>   |- (x = y -> (ph -> A.x(x = y -> ph)))
 
Axioms ax-10 and ax-11
 
Theoremax10o 1176 Show that ax-10o 1177 can be derived from ax-10 1002. An open problem is whether this theorem can be derived from ax-10 1002 and the others when ax-11 1003 is replaced with ax-11o 1255. See theorem ax10 1178 for the rederivation of ax-10 1002 from ax10o 1176.

This theorem should not be referenced in any proof. Instead, use ax-10o 1177 below so that uses of ax-10o 1177 can be more easily identified.

|- (A.x x = y -> (A.xph -> A.yph))
 
Axiomax-10o 1177 Axiom ax-10o 1177 ("o" for "old") was the original version of ax-10 1002, before it was discovered (in May 2008) that the shorter ax-10 1002 could replace it. It appears as Axiom scheme C11' in [Megill] p. 448 (p. 16 of the preprint).

This axiom is redundant, as shown by theorem ax10o 1176.

|- (A.x x = y -> (A.xph -> A.yph))
 
Theoremax10 1178 Rederivation of ax-10 1002 from original version ax-10o 1177. See theorem ax10o 1176 for the derivation of ax-10o 1177 from ax-10 1002.

This theorem should not be referenced in any proof. Instead, use ax-10 1002 above so that uses of ax-10 1002 can be more easily identified.

|- (A.x x = y -> A.y y = x)
 
Theoremalequcom 1179 Commutation law for identical variable specifiers. The antecedent and consequent are true when x and y are substituted with the same variable. Lemma L12 in [Megill] p. 445 (p. 12 of the preprint).
|- (A.x x = y -> A.y y = x)
 
Theoremalequcoms 1180 A commutation rule for identical variable specifiers.
|- (A.x x = y -> ph)   =>   |- (A.y y = x -> ph)
 
Theoremnalequcoms 1181 A commutation rule for distinct variable specifiers.
|- (-. A.x x = y -> ph)   =>   |- (-. A.y y = x -> ph)
 
Theoremhbae 1182 All variables are effectively bound in an identical variable specifier.
|- (A.x x = y -> A.zA.x x = y)
 
Theoremhbaes 1183 Rule that applies hbae 1182 to antecedent.
|- (A.zA.x x = y -> ph)   =>   |- (A.x x = y -> ph)
 
Theoremhbnae 1184 All variables are effectively bound in a distinct variable specifier. Lemma L19 in [Megill] p. 446 (p. 14 of the preprint).
|- (-. A.x x = y -> A.z -. A.x x = y)
 
Theoremhbnaes 1185 Rule that applies hbnae 1184 to antecedent.
|- (A.z -. A.x x = y -> ph)   =>   |- (-. A.x x = y -> ph)
 
Theoremequs3 1186 Lemma used in proofs of substitution properties.
|- (E.x(x = y /\ ph) <-> -. A.x(x = y -> -. ph))
 
Theoremequs4 1187 Lemma used in proofs of substitution properties.
|- (A.x(x = y -> ph) -> E.x(x = y /\ ph))
 
Theoremequsal 1188 A useful equivalence related to substitution.
|- (ps -> A.xps)   &   |- (x = y -> (ph <-> ps))   =>   |- (A.x(x = y -> ph) <-> ps)
 
Theoremequsex 1189 A useful equivalence related to substitution.
|- (ps -> A.xps)   &   |- (x = y -> (ph <-> ps))   =>   |- (E.x(x = y /\ ph) <-> ps)
 
TheoremdvelimfALT 1190 Proof of dvelimf 1288 without using ax-11 1003. See dvelimALT 1392 for a proof (of the distinct variable version dvelim 1391) that doesn't require ax-10 1002.
|- (ph -> A.xph)   &   |- (ps -> A.zps)   &   |- (z = y -> (ph <-> ps))   =>   |- (-. A.x x = y -> (ps -> A.xps))
 
Theoremdral1 1191 Formula-building lemma for use with the Distinctor Reduction Theorem. Part of Theorem 9.4 of [Megill] p. 448 (p. 16 of preprint).
|- (A.x x = y -> (ph <-> ps))   =>   |- (A.x x = y -> (A.xph <-> A.yps))
 
Theoremdral2 1192 Formula-building lemma for use with the Distinctor Reduction Theorem. Part of Theorem 9.4 of [Megill] p. 448 (p. 16 of preprint).
|- (A.x x = y -> (ph <-> ps))   =>   |- (A.x x = y -> (A.zph <-> A.zps))
 
Theoremdrex1 1193 Formula-building lemma for use with the Distinctor Reduction Theorem. Part of Theorem 9.4 of [Megill] p. 448 (p. 16 of preprint).
|- (A.x x = y -> (ph <-> ps))   =>   |- (A.x x = y -> (E.xph <-> E.yps))
 
Theoremdrex2 1194 Formula-building lemma for use with the Distinctor Reduction Theorem. Part of Theorem 9.4 of [Megill] p. 448 (p. 16 of preprint).
|- (A.x x = y -> (ph <-> ps))   =>   |- (A.x x = y -> (E.zph <-> E.zps))
 
Theorema4imt 1195 Closed theorem form of a4im 1196.
|- (A.x((ps -> A.xps) /\ (x = y -> (ph -> ps))) -> (A.xph -> ps))
 
Theorema4im 1196 Specialization, using implicit substitition. Compare Lemma 14 of [Tarski] p. 70. The a4im 1196 series of theorems requires that only one direction of the substitution hypothesis hold.
|- (ps -> A.xps)   &   |- (x = y -> (ph -> ps))   =>   |- (A.xph -> ps)
 
Theorema4ime 1197 Existential introduction, using implicit substitition. Compare Lemma 14 of [Tarski] p. 70.
|- (ph -> A.xph)   &   |- (x = y -> (ph -> ps))   =>   |- (ph -> E.xps)
 
Theorema4imed 1198 Deduction version of a4ime 1197.
|- (ch -> A.xch)   &   |- (ch -> (ph -> A.xph))   &   |- (x = y -> (ph -> ps))   =>   |- (ch -> (ph -> E.xps))
 
Theoremcbv1 1199 Rule used to change bound variables, using implicit substitition.
|- (ph -> (ps -> A.yps))   &   |- (ph -> (ch -> A.xch))   &   |- (ph -> (x = y -> (ps -> ch)))   =>   |- (A.xA.yph -> (A.xps -> A.ych))
 
Theoremcbv2 1200 Rule used to change bound variables, using implicit substitition.
|- (ph -> (ps -> A.yps))   &   |- (ph -> (ch -> A.xch))   &   |- (ph -> (x = y -> (ps <-> ch)))   =>   |- (A.xA.yph -> (A.xps <-> A.ych))

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