Merge pull request #43 from cardano-scaling/zliu41/landing

Populate Plutus landing page

Author: zliu41

src/plutus/README.md

@@ -1 +1,28 @@
 # Plutus
+
+Plutus is Cardano’s on-chain smart contract platform.
+Smart contracts can be written in a variety of languages, and compiled down to Untyped Plutus Core (UPLC), which is executed by validating nodes.
+UPLC is a small functional language based on untyped lambda calculus.
+
+Untyped lambda calculus is Turing-complete, and hence is in theory capable of performing any computation; however for efficiency reasons, UPLC includes an extensible collection of built-in types and functions.
+UPLC is executed by a CEK machine.
+A production implementation should be carefully engineered to maximize performance and support accurate tracking of execution costs.
+
+The CEK machine tracks CPU and memory usage via a cost model.
+There are two kinds of cost: each step the CEK machine takes (e.g., looking up a variable or processing a lambda abstraction) incurs a fixed charge; each call to a built- in function incurs a cost calculated by a costing function - a Haskell function that estimates resource usage based on the sizes of the arguments.
+These are derived empirically by benchmarking the implementation with representative inputs, then using the R statistical system to fit models (e.g., 𝛼 + 𝛽𝑥𝑦 for integer multiplication, where 𝑥 and 𝑦 are the numbers of machine words required to store the arguments).
+These functions are used for deterministic and efficient costing for script execution.
+
+## Resources
+
+- [Plinth User Guide](https://plutus.cardano.intersectmbo.org/docs/): This up-to-date guide not only covers Plinth (a Haskell-based surface language) and its compilation to UPLC, but also explains many core concepts.
+If you are relatively new to this space, start with this guide, and follow the "Essential concepts" and "Glossary" sections.
+
+- [Plutus Core Specification](https://plutus.cardano.intersectmbo.org/resources/plutus-core-spec.pdf): Studying the spec ensures your own implementation adheres to the exact language rules.
+The specification is periodically updated as new primitives and features are added to the language.
+This blueprint covers the portion of the specification relevant to CEK machine implementation, presented in a more approachable and readable format.
+
+- Haskell implementation: The plutus repository contains a highly optimized Haskell implementation of the CEK machine, used in the Haskell node.
+You can find the Haddock [here](https://plutus.cardano.intersectmbo.org/haddock/latest/plutus-core/UntypedPlutusCore-Evaluation-Machine-Cek.html).
+
+- [CEK machine Wikipedia page](https://en.wikipedia.org/wiki/CEK_Machine).