The following presents a system of pattern matching which can be used to recognize patterns of characters. a-z<> Most characters are literal. For example, "a" matches "a" but no other strings. . Dot, ".", will match any single character Therefore "a. b" will match "aab", "abb", "a1b", "a&b", … […] Square brackets will match any character that is listed within the [ ]. Therefore "a[ghi]b" will match "agb", "ahb", "aib" but nothing else. ? means "the previous item is optional" Therefore "ab?c" will match "ac" and "abc" but nothing else. * means "zero or more of the previous item" Therefore "ab*c" will match "ac", "abc", "abbc", "ac", … + means "one or more of the previous item" Therefore "ab+c" will match "abc", "abbc", "abbbc", "ac", … ( ) means "group the items together" Therefore "a(bc)+d" will match "abcd", "abcbcd", "abcbcbcd", … | means "one expression or the other" Therefore "a(bcd|efg)h" will match "abcdh" or "aefgh" Which pattern will match strings "a", "de<'f','g'>", and "hij<'k','l'>" but will not match "h", and not match "" ?