YES We show the termination of the TRS R: app(app(map(),f),nil()) -> nil() app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) app(app(treemap(),f),app(app(node(),x),xs)) -> app(app(node(),app(f,x)),app(app(map(),app(treemap(),f)),xs)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(cons(),app(f,x)),app(app(map(),f),xs)) p2: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(cons(),app(f,x)) p3: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(f,x) p4: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) p5: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(app(node(),app(f,x)),app(app(map(),app(treemap(),f)),xs)) p6: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(node(),app(f,x)) p7: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(f,x) p8: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(app(map(),app(treemap(),f)),xs) p9: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(map(),app(treemap(),f)) and R consists of: r1: app(app(map(),f),nil()) -> nil() r2: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r3: app(app(treemap(),f),app(app(node(),x),xs)) -> app(app(node(),app(f,x)),app(app(map(),app(treemap(),f)),xs)) The estimated dependency graph contains the following SCCs: {p3, p4, p7, p8} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(f,x) p2: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(app(map(),app(treemap(),f)),xs) p3: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) p4: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(f,x) and R consists of: r1: app(app(map(),f),nil()) -> nil() r2: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r3: app(app(treemap(),f),app(app(node(),x),xs)) -> app(app(node(),app(f,x)),app(app(map(),app(treemap(),f)),xs)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: app#_A(x1,x2) = ((0,0),(1,0)) x2 + (3,3) app_A(x1,x2) = ((1,0),(0,0)) x1 + x2 + (7,23) map_A() = (2,24) cons_A() = (8,25) treemap_A() = (4,1) node_A() = (5,2) precedence: app# = app = map = cons = treemap = node partial status: pi(app#) = [] pi(app) = [] pi(map) = [] pi(cons) = [] pi(treemap) = [] pi(node) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: app#_A(x1,x2) = (1,1) app_A(x1,x2) = (5,5) map_A() = (2,2) cons_A() = (3,3) treemap_A() = (3,3) node_A() = (4,4) precedence: treemap = node > cons > app# = app = map partial status: pi(app#) = [] pi(app) = [] pi(map) = [] pi(cons) = [] pi(treemap) = [] pi(node) = [] The next rules are strictly ordered: p1 We remove them from the problem. -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(app(map(),app(treemap(),f)),xs) p2: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) p3: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(f,x) and R consists of: r1: app(app(map(),f),nil()) -> nil() r2: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r3: app(app(treemap(),f),app(app(node(),x),xs)) -> app(app(node(),app(f,x)),app(app(map(),app(treemap(),f)),xs)) The estimated dependency graph contains the following SCCs: {p3} {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(treemap(),f),app(app(node(),x),xs)) -> app#(f,x) and R consists of: r1: app(app(map(),f),nil()) -> nil() r2: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r3: app(app(treemap(),f),app(app(node(),x),xs)) -> app(app(node(),app(f,x)),app(app(map(),app(treemap(),f)),xs)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: app#_A(x1,x2) = ((1,0),(1,1)) x1 + (4,4) app_A(x1,x2) = x1 + ((1,0),(1,1)) x2 + (2,2) treemap_A() = (5,1) node_A() = (1,1) precedence: app# = app = treemap = node partial status: pi(app#) = [] pi(app) = [] pi(treemap) = [] pi(node) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: app#_A(x1,x2) = (1,2) app_A(x1,x2) = ((1,0),(0,0)) x1 + ((1,0),(0,0)) x2 + (1,3) treemap_A() = (2,1) node_A() = (2,3) precedence: app# = app > treemap = node partial status: pi(app#) = [] pi(app) = [] pi(treemap) = [] pi(node) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: app#(app(map(),f),app(app(cons(),x),xs)) -> app#(app(map(),f),xs) and R consists of: r1: app(app(map(),f),nil()) -> nil() r2: app(app(map(),f),app(app(cons(),x),xs)) -> app(app(cons(),app(f,x)),app(app(map(),f),xs)) r3: app(app(treemap(),f),app(app(node(),x),xs)) -> app(app(node(),app(f,x)),app(app(map(),app(treemap(),f)),xs)) The set of usable rules consists of (no rules) Take the reduction pair: lexicographic combination of reduction pairs: 1. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: app#_A(x1,x2) = ((1,0),(1,1)) x2 + (5,2) app_A(x1,x2) = x2 + (1,3) map_A() = (4,5) cons_A() = (2,4) precedence: app# = app = map = cons partial status: pi(app#) = [] pi(app) = [] pi(map) = [] pi(cons) = [] 2. weighted path order base order: matrix interpretations: carrier: N^2 order: lexicographic order interpretations: app#_A(x1,x2) = ((0,0),(1,0)) x2 + (4,4) app_A(x1,x2) = (2,2) map_A() = (1,1) cons_A() = (3,3) precedence: app = map > cons > app# partial status: pi(app#) = [] pi(app) = [] pi(map) = [] pi(cons) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.