upload diverse filer

Diskret Mat/ipynb filer/test.py

@@ -0,0 +1,57 @@
+from sympy import *
+
+def check_injective_surjective(func, var, domain, codomain):
+    x, y = symbols('x y')
+    
+    # Check if the function is well-defined
+    outputs = {}
+    for val in domain:
+        output = func.subs(var, val)
+        if output in outputs:
+            # If the same output occurs for different inputs, it's not well-defined
+            if outputs[output] != val:
+                return "The function is not well-defined."
+        else:
+            outputs[output] = val
+    
+    # Check injectivity
+    injective = True
+    for val1 in domain:
+        for val2 in domain:
+            if val1 != val2:
+                if func.subs(var, val1) == func.subs(var, val2):
+                    injective = False
+                    break
+    
+    # Check surjectivity
+    surjective = True
+    for c_val in codomain:
+        try:
+            solutions = solve(Eq(func, c_val), var)
+            if not any(s in domain for s in solutions):
+                surjective = False
+                break
+        except:
+            surjective = False
+            break
+    
+    # Results
+    if injective and surjective:
+        return "The function is bijective (both injective and surjective)."
+    elif injective:
+        return "The function is injective only."
+    elif surjective:
+        return "The function is surjective only."
+    else:
+        return "The function is neither injective nor surjective."
+
+# Define the function and its domain/codomain
+x = symbols('x')
+func = Piecewise((2*x, x >= 0), (-2*x-1, x < 0))
+domain = range(-20, 20)  # For example, integers from -20 to 20
+codomain = range(0, 40)  # Adjusted codomain to include all possible outputs
+
+result = check_injective_surjective(func, x, domain, codomain)
+print(result)
+
+print("please double check it yourself")