+HELP: supremum-by
+{ $values
+ { "seq" sequence } { "quot" quotation }
+ { "elt" object }
+}
+{ $description "Outputs the greatest element of " { $snippet "seq" } " according to the " { $snippet "quot" } "." }
+{ $examples
+ "Example:"
+ { $example "USING: sequences prettyprint ;"
+ "{ { 1 2 } { 1 2 3 } { 1 2 3 4 } } [ length ] supremum-by ."
+ "{ 1 2 3 4 }"
+ }
+}
+{ $errors "Throws an error if the sequence is empty." } ;
+
+{ min max infimum infimum-by supremum supremum-by } related-words
+
+HELP: shortest
+{ $values { "seqs" sequence } { "elt" object } }
+{ $description "Outputs the shortest sequence from " { $snippet "seqs" } "." } ;
+
+HELP: longest
+{ $values { "seqs" sequence } { "elt" object } }
+{ $description "Outputs the longest sequence from " { $snippet "seqs" } "." } ;
+
+{ shortest longest } related-words