diff --git a/app/models/logic.rb b/app/models/logic.rb
index ea9552ed3..6945a0db2 100644
--- a/app/models/logic.rb
+++ b/app/models/logic.rb
@@ -8,12 +8,23 @@ module Logic
   end
 
   def self.class_from_name(name)
-    [Constant, Empty]
+    [Constant, Empty, LessThan, LessThanEq, Eq, GreaterThanEq, GreaterThan, EmptyOperator]
       .find { |c| c.name == name }
   end
 
+  def ds_eq(left, right) = Logic::Eq.new(left, right)
+
+  def greater_than(left, right) = Logic::GreaterThan.new(left, right)
+
+  def greater_than_eq(left, right) = Logic::GreaterThanEq.new(left, right)
+
+  def less_than(left, right) = Logic::LessThan.new(left, right)
+
+  def less_than_eq(left, right) = Logic::LessThanEq.new(left, right)
+
   def constant(value) = Logic::Constant.new(value)
 
   def empty = Logic::Empty.new
 
+  def empty_operator(left, right) = Logic::EmptyOperator.new(left, right)
 end
diff --git a/app/models/logic/binary_operator.rb b/app/models/logic/binary_operator.rb
new file mode 100644
index 000000000..85b7fb49c
--- /dev/null
+++ b/app/models/logic/binary_operator.rb
@@ -0,0 +1,46 @@
+class Logic::BinaryOperator < Logic::Term
+  attr_reader :left, :right
+
+  def initialize(left, right)
+    @left, @right = left, right
+  end
+
+  def to_h
+    {
+      "op" => self.class.name,
+      "left" => @left.to_h,
+      "right" => @right.to_h
+    }
+  end
+
+  def self.from_h(h)
+    self.new(Logic.from_h(h['left']), Logic.from_h(h['right']))
+  end
+
+  def errors(stable_ids = [])
+    errors = []
+
+    if @left.type != :number || @right.type != :number
+      errors += ["les types sont incompatibles : #{self}"]
+    end
+
+    errors + @left.errors(stable_ids) + @right.errors(stable_ids)
+  end
+
+  def type = :boolean
+
+  def compute(champs = [])
+    l = @left.compute(champs)
+    r = @right.compute(champs)
+
+    l.send(operation, r)
+  end
+
+  def to_s = "(#{@left} #{operation} #{@right})"
+
+  def ==(other)
+    self.class == other.class &&
+      @left == other.left &&
+      @right == other.right
+  end
+end
diff --git a/app/models/logic/empty_operator.rb b/app/models/logic/empty_operator.rb
new file mode 100644
index 000000000..44ab38c40
--- /dev/null
+++ b/app/models/logic/empty_operator.rb
@@ -0,0 +1,7 @@
+class Logic::EmptyOperator < Logic::BinaryOperator
+  def to_s = "empty operator"
+
+  def type = :empty
+
+  def errors(_stable_ids = nil) = ['empty']
+end
diff --git a/app/models/logic/greater_than.rb b/app/models/logic/greater_than.rb
new file mode 100644
index 000000000..2ba94af0f
--- /dev/null
+++ b/app/models/logic/greater_than.rb
@@ -0,0 +1,3 @@
+class Logic::GreaterThan < Logic::BinaryOperator
+  def operation = :>
+end
diff --git a/app/models/logic/greater_than_eq.rb b/app/models/logic/greater_than_eq.rb
new file mode 100644
index 000000000..d452bceef
--- /dev/null
+++ b/app/models/logic/greater_than_eq.rb
@@ -0,0 +1,3 @@
+class Logic::GreaterThanEq < Logic::BinaryOperator
+  def operation = :>=
+end
diff --git a/app/models/logic/less_than.rb b/app/models/logic/less_than.rb
new file mode 100644
index 000000000..b39282ee7
--- /dev/null
+++ b/app/models/logic/less_than.rb
@@ -0,0 +1,3 @@
+class Logic::LessThan < Logic::BinaryOperator
+  def operation = :<
+end
diff --git a/app/models/logic/less_than_eq.rb b/app/models/logic/less_than_eq.rb
new file mode 100644
index 000000000..79e4c7308
--- /dev/null
+++ b/app/models/logic/less_than_eq.rb
@@ -0,0 +1,3 @@
+class Logic::LessThanEq < Logic::BinaryOperator
+  def operation = :<=
+end
diff --git a/spec/models/logic/binary_operator_spec.rb b/spec/models/logic/binary_operator_spec.rb
new file mode 100644
index 000000000..de145514c
--- /dev/null
+++ b/spec/models/logic/binary_operator_spec.rb
@@ -0,0 +1,52 @@
+include Logic
+
+describe Logic::BinaryOperator do
+  let(:two_greater_than_one) { greater_than(constant(2), constant(1))}
+
+  describe '#type' do
+    it { expect(two_greater_than_one.type).to eq(:boolean) }
+  end
+
+  describe '#to_s' do
+    it { expect(two_greater_than_one.to_s).to eq('(2 > 1)') }
+  end
+
+  describe '#==' do
+    it { expect(two_greater_than_one).to eq(greater_than(constant(2), constant(1))) }
+    it { expect(two_greater_than_one).not_to eq(greater_than(constant(1), constant(2))) }
+  end
+
+  describe '#errors' do
+    it { expect(greater_than(constant(1), constant(true)).errors).to eq(['les types sont incompatibles : (1 > true)']) }
+  end
+end
+
+describe Logic::GreaterThan do
+  it 'computes' do
+    expect(greater_than(constant(1), constant(1)).compute).to be(false)
+    expect(greater_than(constant(2), constant(1)).compute).to be(true)
+  end
+end
+
+describe Logic::GreaterThanEq do
+  it 'computes' do
+    expect(greater_than_eq(constant(0), constant(1)).compute).to be(false)
+    expect(greater_than_eq(constant(1), constant(1)).compute).to be(true)
+    expect(greater_than_eq(constant(2), constant(1)).compute).to be(true)
+  end
+end
+
+describe Logic::LessThan do
+  it 'computes' do
+    expect(less_than(constant(1), constant(1)).compute).to be(false)
+    expect(less_than(constant(1), constant(2)).compute).to be(true)
+  end
+end
+
+describe Logic::LessThanEq do
+  it 'computes' do
+    expect(less_than_eq(constant(0), constant(1)).compute).to be(true)
+    expect(less_than_eq(constant(1), constant(1)).compute).to be(true)
+    expect(less_than_eq(constant(2), constant(1)).compute).to be(false)
+  end
+end
diff --git a/spec/models/logic_spec.rb b/spec/models/logic_spec.rb
index 43a017a4f..abd5fcc41 100644
--- a/spec/models/logic_spec.rb
+++ b/spec/models/logic_spec.rb
@@ -6,5 +6,7 @@ describe Logic do
     expect(Logic.from_json(constant(1).to_json)).to eq(constant(1))
 
     expect(Logic.from_h(empty.to_h)).to eq(empty)
+
+    expect(Logic.from_h(greater_than(constant(1), constant(2)).to_h)).to eq(greater_than(constant(1), constant(2)))
   end
 end