-- PRIMSPROOF Derivation of 2^3^4^5^6^7^8^9^10^11^12^13^14^15 Rewriting the preceding term leads to 5^2^3^4^6^7^8^9^10^11^12^13^14 Rewriting the preceding term leads to 7^5^2^3^4^6^8^9^10^11^12^13 Rewriting the preceding term leads to 6^3^7^5^2^4^8^9^10^13^11 Rewriting the preceding term leads to 3^11^13^10^9^8^4^2^5^7 Rewriting the preceding term leads to 5^7^2^4^8^9^3^13^11 Rewriting the preceding term leads to 2^11^3^13^9^8^5^7 Rewriting the preceding term leads to 2^11^3^13^9^7^5 Rewriting the preceding term leads to 3^2^11^13^5^7 Number of proof steps: 8