@{ ${ fold right @{$Px} rec acc @{'exists (λ${ident x}.$acc)} } }
}.
+notation < "hvbox(\Sigma ident i opt (: ty) break . p)"
+ right associative with precedence 20
+for @{ 'sigma ${default
+ @{\lambda ${ident i} : $ty. $p}
+ @{\lambda ${ident i} . $p}}}.
+
+notation > "\Sigma list1 ident x sep , opt (: T). term 19 Px"
+ with precedence 20
+ for ${ default
+ @{ ${ fold right @{$Px} rec acc @{'sigma (λ${ident x}:$T.$acc)} } }
+ @{ ${ fold right @{$Px} rec acc @{'sigma (λ${ident x}.$acc)} } }
+ }.
+
notation "hvbox(\langle term 19 a, break term 19 b\rangle)"
with precedence 90 for @{ 'pair $a $b}.
notation > "hvbox({ ident i | term 19 p })" with precedence 90
for @{ 'subset (\lambda ${ident i}. $p)}.
+notation < "hvbox({ ident i ∈ s | term 19 p })" with precedence 90
+for @{ 'comprehension $s (\lambda ${ident i} : $nonexistent . $p)}.
+
+notation > "hvbox({ ident i ∈ s | term 19 p })" with precedence 90
+for @{ 'comprehension $s (\lambda ${ident i}. $p)}.
+
notation "hvbox(a break ∈ b)" non associative with precedence 45
for @{ 'mem $a $b }.
left associative with precedence 55
for @{ 'compose $a $b }.
+notation "↓a" with precedence 55 for @{ 'downarrow $a }.
+
+notation "hvbox(U break ↓ V)" non associative with precedence 55 for @{ 'fintersects $U $V }.
+
+notation "↑a" with precedence 55 for @{ 'uparrow $a }.
+
+notation "hvbox(a break ↑ b)" with precedence 55 for @{ 'funion $a $b }.
+
notation "(a \sup b)" left associative with precedence 60 for @{ 'exp $a $b}.
notation "s \sup (-1)" with precedence 60 for @{ 'invert $s }.
notation < "s \sup (-1) x" with precedence 60 for @{ 'invert_appl $s $x}.
+notation "hvbox(|term 90 C|)" with precedence 69 for @{ 'card $C }.
notation "\naturals" non associative with precedence 90 for @{'N}.
notation "\rationals" non associative with precedence 90 for @{'Q}.